Sarah Michelle Gellar and David Boreanaz have created one of the best (if not the best one) TV couple of all time! What made them so special, what was the reason they were so real ?

One word: Chemistry. This is the key. And it's not only about the great working relationship they had, but it's even more about how they felt about each other in real life. You can see a lot of screen couples which in a movie or series play great loves but in reality barely stand each other (e.g.Patrick Swayze and Jennifer Grey), or simply don't share any special friendship, just regular working relationship. The things are different when it comes to Sarah and David, the big reason they were able to create such a beautiful and deep relationship and love story on screen is the fact they both were bonding in a real life. I don't know any other TV lovers who would be that close in their real lives. Fans all over the world still speculates was there something more ? I'm convinced there was. Just look at their body language, the way they looked at each other, or simply how they enjoyed the time spending together, you could see them always as close as possible, hugging and smiling. Sarah was just glowing when she was around him. And trust me that is not typical Sarah Michelle Gellar behavior with colleagues she's working with. There are pictures of her with James Marsters, Nicholas Bendon or Seth Green and all you can see there is 'good friends from the same show'
According to sources like Wikipedia, whodatedwho.com etc. they were (SMG&DB) dating around 1998-99 (seasons 2-3 of BTVS). Sarah was at that time single and David recently divorced (or in separation) with his first wife Ingrid Quinn. They (SMG&DB) were appearing together a lot, you can easily find a lot pictures where you will find happy Sarah in David's arms, smiling one to another or look deep into each others eyes. And don't tell me that this is 'regular friends typical behavior' because it definitely doesn't ;) 'Just friends' don't kiss in front of the cameras.

About working together...

The way they both talk about working together is always great to listen to. For all the time they spend on the set, they never had an argument, both always had each others back. They were support to each other, and because of the private connection, great friendship they shared, it was easier for them to show all those difficult emotions, it's called security. Sometimes when I watch their scenes, especially those romantic ones (so, its like all of them;)) I got the impression this is so good because they really mean that.
Sarah, once said: "We had the most amazing working relationship I've ever had,
I've been very blessed with the guys that I've worked opposite, but David and I had a very, very special relationship. In three years of working together, we never had so much as a disagreement, and that's just unbelievable, considering the hours we spent together."
Also David praises work with SMG: "I mean working with her is great. The three seasons that we worked together, we never had an argument.
I mean that's pretty odd, um -since we were in such close quarters, both of our characters.
But, you know she's here in my heart, and that's the best thing about it. And she's actually given me the opportunity to be here where I am today.
I mean her character, her show, enabled me to grow and become another character so I owe a lot to her."
What's essential in making good job is to have a good and trusted partner. This is what they both had. The reason Buffy/Angel relationship is so real, touching, heartbreaking and deep is the fact both actors gave their best, put whole emotions into it, and both were identifying with their characters and with what they were going through in their relationship. SMG felt all the emotions, struggles and pain her fictional character was going through, this is another reason why it was so real and so good, she said: "Last year, with Angel and the heartbreak, I would go home and cry. My body wouldn't work properly. I don't take demons home with me, but I do take Buffy's pain.
The vampires I'm immune to, but not the emotion.
When we filmed the episode where Angel breaks up with her, I cried for 25 minutes. I thought I was having a breakdown. They had to shut down the set. When they say rip your heart out, that's really what unfulfilled love does."
The question is, what made Sarah like that, apart from the fact, Buffy was close to her and she understood her, what caused her emotions were that strong ? I think it was David who had that impact on her, here's some fan comment about them two, which really made me think more and simply intrigued me:
"My theory is that they dated. Fell in love.. Were basically Buffy and Angel - the supernatural stuff. Then they broke up for who knows what reason with broken hearts. and That`s y u never hear anything about it.. Cuz it hurts to much for them to talk about. I`m not much for romance.. But the way those 2 went together... I`m not sure anyones that good an actor. Just one girls opinion." and if you will think more about it, that makes some sense.

They knew: There's nothing else beyond that relationship...

I personally believe that true love happens only once in your entire life. That's why I'm completely resistant on connections such as Spuffy, Briley or Cangel - I just don't believe it and there's no that sparkle Bangel has. But you know what they say: Show must go on! We couldn't expect that Angel after leaving Sunnydale will live in solitude, and will never again try some new relationship, we also couldn't expect that for the rest of the show Buffy remain single. But come on. Do you really believe Buffy and Angel after all they been through, could truly love someone else ?
Just recall 'Chosen' episode. Buffy had a thing with Spike (whatever it was) Angel was in a relationship with Cordelia, and did they feel bad about their kiss ? No, because their love never stopped, and all the other relationships are just that 'opposite ones'. Don't take me wrong this is not against Spuffy or Cangel etc. fans. I respect someone may have different opinion than mine and just look for something else, appreciate and like different things, but let's face it BANGEL is that main relationship and pinnacle of everything.
If Angel's feelings for Cordelia were true, he would never start this conversation:

Angel: “Any thoughts on who might enjoy— Do I have to go with the cookie analogy?”
Buffy: “I’m not really thinking that far ahead. That’s kind of the point.”
Angel: “I’ll go start working on the second front. Make sure I don’t have to use it.”
Buffy: “Angel. I do... sometimes think that far ahead.”
Angel: “Sometimes is something.”
Buffy: “Be a long time coming. Years, if ever.”
Angel: “I ain’t getting any older.”

You see the point ? It will be always like that, no matter with whom they both will be, no matter how long they will be apart. They will always be dreaming about each other and willing to finally be together forever, because this is the truest love.
Both Sarah and David are of course total Bangel shippers, and who can know Buffy and Angel better than them ?;). Sarah always keep saying Angel is Buffy's true love and they should be together forever, David said that Buffy (in Angel series) is a spectre of his ONE true love, and there's nothing else beyond that relationship (B/A).

Full quotes:

DB: I don't see anything else beyond that relationship. We know they'll end up together.
- David Boreanaz on is Angel Buffy's true love

SMG: about Buffy finale: There is a definite connection between Buffy and Angel. It's love in its truest most pure form."

DB: For Angel, the love of his life is definitely Buffy

DB: The Buffy-Angel connection has got to win out (in the end). They're perfect together.

SMG: Every time they try and bring someone new in for Buffy, all I can think is, "But it's not Angel!".
I'm not really sure what we're going to do now. We just did an interesting episode where Buffy spent the summer moping over her boyfriend...
like everybody who loses their first love...

Sarah Michelle Gellar & David Boreanaz never confirmed or denied their secret relationship off set. I think we will never know how it was, but we can see and we can read the signs, which shows obviously, that the thing they had was just like David said "different and unique", and I'm sure it was not only about working together.
They always talk about each other in the best possible way, not so long time ago DB tweeted: "Welcome back SMG with The Ringer...break a leg"
After so many years they still keep in touch and whenever they meet that unforgettable chemistry is still there... ♥

Sources:

Photos: courtesy of: d-boreanaz.com,
sarahmichellegellarfans.com,
sarahmichelle-gellar.com
Google Search
Quotes from: backtothehellmouth.angelfire.com/CastCrewQuotes.html
fanpop.com/spots/sarah-and-david
videos from youtube.com

If you are interested in my other Bangel article, here's the link: link

Sometimes pictures are worth more than a thousand words, so take a look and draw conclusion on your own ;)