The thing is what they are both looking for is a good looking person who will give them attention. There's plenty of girls who are Stan-tier in both looks and attitude but surprise, surprise, Stan would rather wank to super models and dream they'll accept his sword.You know what's funny about Louise's hate for Stan. She is so desperate for attention and affection from any source she can find it and Stan seems like he'd be totally devoted to any girl who'd give him attention and affection. They're both looking for the same thing and you'd think they'd get on great if they got together.
And while Louise is decent enough looking to maybe meet Stan's inflated standards of what girl he "deserves", Stan is obv. not meeting similar standards Louise is setting for her potential partner.