Loud exhausts everywhere - pickups, domestic V6/V8's, motorcycles.
Super-bright headlights/aux lights improperly mounted or operated, blinding you at night.
Stereos you can almost feel before you hear them.
All these guys (and let's face it, it's 90% guys doing the irritating stuff) are being sold a dream by the mod manufacturers that if they just install this $1500 catback or this $1000 sub they will finally get the respect they deserve.
They get online forum/Facebook/Insta/TikTok validation but very few people around them are impressed with their choices.
I mainly hate how people are being taken for a ride (pardon the pun) by marketers and putting money into things that aren't really going to improve their car-driving experience.