I guess mine would have to be that sims actually age and gain weight over time. Sure sometimes it's annoying that a sim in a household I haven't played in a while is a bit more 'substantial.' But I like that they change over the course of time and aren't all perfect sugar cookies. And another unpopular opinion is that townies dress like they don't have mirrors. I get a kick out of their outfits some times. "You are rocking that bright orange sweater/cowboy boot outfit today!"