I always found people who take pictures with the middle finger as a trashy gesture. I don’t and never know who they’re trying to tell off but it’s out of no where and just stupid. It doesn’t offend me, I just find it a pointless gesture and therefore - trashy.
Getting too emotional, positively or negatively, about any sports team you don’t have a real personal connection to (as in, your dad founded it, your brother plays in it, something like that, not just “well I was born in Shitstreak so I’m a proud Shitstreaker!”) or that you haven’t bet any money on. Additionally, betting money on sports or any sort of gambling, which can go from trashy and desperate to degenerate and pathological.