Because he didn't know her back then. But now he does.
--> Because he's the bad boy and she the sweet model.
--> Because he is jealous when Izzie is with another guy.
--> Because he still had feelings for her
--> Because she didn't want Alex to move in considering their past.
--> Because they're hot.
--> Because they love each other.
--> Because they are friends.
--> Because they both let Cristina of the hook.
--> Because she orders everything he said.
--> Because Izzie is the first one in the hospital that sees that Alex is okay.
--> Because they blew away an eyelash together.
--> Because he thinks she deserves to have someone.
--> Because she didn't want to believe that he is really over her.
--> Because he is jealous of O'Malley.
--> Because she thinks he is so offensive and yet so charming all at the same time.
--> Because he asks her out for real.
--> Because they give the rest something to talk about.
--> Because Alex and Izzie do not believe you.
--> Because he had a good time on their date.
--> Because he plans to kiss her a lot more.
--> Because they both can't sleep.
--> Because he likes her rack, but can do without it, because all he wants is her.
--> Because she forgave him.
--> Because she helped her practising for his test.
--> Because she opened up his testresults.
--> Because he never wanted to hurt her.
--> Because she wants him to take off his pants.
--> Because he carried her away from Dennie.
--> Because he is the one that got her home, after waiting outside the hospital all day.
--> Because he feels guilty about what happened to Izzie.
--> Because he makes the grand gesture.
--> Because they like talking about themselves in the 3rd person.
--> Because she thinks that he rocks.
--> Because she buys him a drink.
--> Because they steal patients together from the ER.
--> Because he has seen it all before.
--> Because he is defenitely interested.
--> Because they're cute when they kiss.
--> Because she is to important to him, that he couldn't do it.
--> Because they were having a good time.
--> Because he told her the truth.
--> Because he is embarassed, for her sleeping with O'Malley.
--> Because they both are "the other person".
--> Because from all her friends, she told him first about George.
--> Because they both think Callie is a bitch.
--> Because Alex brings her a tissue box when she cries.
--> Because he acts like an ass when everyone but Izzie is around.
--> Because he blushes when Meredith says that Izzie likes him.
--> Because she shaved her legs for him. She only shaved one leg for George.
--> Because she put him on the pager list for the quints surgery.
--> Because he let his emotions get in the way and couldn't do it.
--> Because according to Izzie, they're all pulling for him.
--> Because Izzie is being a doer.
--> Because she is saying yes.
--> Because he told her it's gonna be okay.
--> Because they have dirty in their eyes.
--> Because the food that Alex gave, was good food.
--> Because they both look nice at prom.
--> Because it's his freaking team.
--> Because Alex knew she wouldn't last a year, when they first met.
--> Because they have chemistry.
Because he shows a different side when he's around her
--> Because he made two grand gestures for her already.
--> Because she ran from George to Alex (2x19)
--> Because he is embarassed for her.
--> Because he swears not to tell anybody.
--> Because he is shocked to find out about George and she knows.
--> Because he cares about her and George.
--> Because he needs her help.
--> Because she is the opposite of him, an optimist.
--> Because Yang got's nothing on her.
--> Because he tells only her something real about his past.
--> Because he cares enought to yell at her.
--> Because Izzie wants to tell him about the fake pregnacy but she isn't allowed to.
--> Because she covers hist post-ups.
--> Because Izzie tells Lexie: Everything we do for the people we love. She was trying to help Alex at that moment.
--> Because Izzie kissed him back.
--> Because she doesn't listen when he tells her to stay out of his life.
--> Because she asks Bailey for help with Alex.
--> Because he calls her Iz.
--> Because she is sorry
--> Because he just wants her this once.
--> Because she keeps asking if he's okay.
--> Because he thanks her for asking.
--> Because she wants them to live together if Meredith moves them out.
--> Because he said 'Hello'.
--> Because he has the possibility of something to live for.
--> Because they fight at the stairwell all the time.
--> Because Izzie wants him to pick who he's gonna be.
--> Because she cares about him.
--> Because she knows he cares about her too.
--> Because she wants him to admit it.
--> Because it's not to late for them.
--> Because he's asking if she's all-in.
--> Because he wants lessons.
--> Because he doesn't want them to see other people.
--> Because they want to go steady.
--> Because he wants to cheer her up.
--> Because she thanks him for bringing her corpses.
--> Because he loves her.
--> Because she thinks he deserves better when she is not feeling well
--> Because he can handle the mess. He is not going anywhere.
--> Because the first thing Alex did after he won the first solo surgery was look for Izzie.
--> Because he is not gonna cheat on her or die.
--> Because she makes him better.
--> Because she makes him wanna be better.
--> Because he wants Izzie to scrub in with him.
--> Because they both want to try 16.
--> Because she thinks he is gonna be a rockstar.
--> Because she can totally see him in 10 years with a stethoscope around his neck, charting. A big shot attending.
--> Because she wants to fantasize about her boyfriend and his big big future.
--> Because he defends her: Izzie is nothing like the new O'Malley.
--> Because he thinks it's great that she likes teaching.
--> Because they can be great together.
--> Because he doesn't want to be the future of the hospital if she is not there with him.
--> Because Izzie isn't just any patient according to Alex.
--> Because he wants the cup.
--> Because he feels guilty, he didn't listen to her about the ghost.
--> Because he is there for her.
--> Because he snooched into a cup for her and she thanks him.
--> Because he tastes food for her.
--> Because he rather kiss her than give her a high-five.
--> Because Alex is the man she loves.
--> Because he cares about her health more than the wedding.
--> Because he doesn't want George to worry about Izzie. He wants to do it himself.
--> Because the dress isn't for Meredith.
--> Because we are gathered here today to celebrate the wedding of Alexander Michael Karev and Isobel Katherine stevens.
--> Because today is the day his life begins.
--> Because today their life together begins. And they can't wait.
--> Because they kiss before the minister is finished.
--> Because he thinks she looks good bald anyway.
--> Because he has never cried as much since Izzie got sick.
--> Because his wife is hot.
--> Because he wants her to have the surgery.
--> Because Izzie's husband has a fine ass.
--> Because she wants him to meet her patient friends.
--> Because he wants her to help get her memory back.
--> Because he cares enought to fight with her.
--> Because he wants to screw the DNR!