I still laugh whenever I get presented with the choice of leaving Kaidan or Ashley "you just wait right here Kaidan. We'll be right back "
And its actually some bs. On one playthrough I finally decided to throw Ashley in the bushes for being a space republican. Kaidan's backstory and motivations are actually really, really damned good - his personality and punchable face just make him one of the weakest male characters on the ship when it comes to how he relates to Shepard.
In ME3 for example, when he's in the hospital recovering, he says some more than a couple of times. In the end, he's a better character than a lot of the cast - he's just never a breh like Garrus, Mordin, Wrex, or even Jacob for that matter.
First run I was suspect of Ashley, she's always "You bringing more aliens on board?!"' You hear more of her backstory and you understand. I aligned more with Kaidan due to his backstory and politics but I threw him to the bushes to smash Ashley.