I can't think of any character or ship that fandom has made me love (though certainly there are some that fandom has made me appreciate more; I'll be honest, I'm not a Dawn fan, but the Spuffy group we were in kept me from hating her), but I absolutely hate Destiel because of the fandom, and I don't much care for Cas himself either. If I'm just watching the show and can compartmentalize, I don't usually mind Cas, and objectively, I can see why people would ship him and Dean (I've written one Destiel one-shot myself), but I have to block it on Tumblr because Destiel fandom comes with irrational Sam hatred/erasure and a whole lot of delusions about Dean's characterization. :)))