I've got lots of good friends that are Cubs fans and even White Sox fans. I have yet to visit Busch Stadium for a game but I usually enjoy Wrigley when the Cards are in town. IME Cards fans tend to be pretty knowledgeable about baseball in general and can be fun to engage in convo's at the park. I once sat next to a group up from St. Louis; they explained they were teachers and always took a group trip on the Amtrak up for a weekend series to enjoy Chicago and baseball. Of course this was back before interleague play and "balanced" schedules when MLB knew enough to make sure there was AT LEAST one weekend series in both cities.
I never hated the Cards or their fans. I hated that the Cubs were always LOSING to them!
IME there is, unfortunately, plenty of obnoxious fans to go around including Cubs fans I've seen where I think "Damn, I *really* wish he wasn't on my side".
Thinking about various fans that DO tend to rub me wrong at the ballpark (these are, of course, broad generalizations that are probably very unfair. Sue me!) . . .
Yankees fans. EVERYTHING is better in NY. How do I know? Because they will tell you even though you didn't ask. For every. single. thing. Yeah, yeah, your team is better. Your stadium's better. Your subway's better. Even your muggers are better, I GET IT!
Braves fans. It's nice you lifted the tomahawk chant from FSU without attribution but realize that after the 13th or so time it wears a little thin. But thanks for not showing up at your OWN playoff games all those years where I could fly down and pick up seats, cheap, and stay with my sister for free.
Mets fans. 'nuff said.