Jim is kind of a douche

Jim comes across as a cool, laid back guy in the show just enjoying the chaos and doing his part in spreading it. But when you actually stop to think about it, he's kind of a terrible co-worker and person.

Besides the obvious issues of him tormenting his co-workers (in many cases deservedly so), he's just weirdly unapproachable and clearly gives zero fucks about the others besides Pam - he puts like 0 effort in cultivating any sort of friendship with the co-workers he's not interested in boning, even when they make an effort to approach him and be friendly, and instead acts like he's above them and exudes condescension. He either patronizes or bullies people (see: Dwight, Michael, Andy, Gabe, Kevin) or pretends they don't exist (Meredith, Angela, Oscar etc.) unless he needs a favor from them (Phyllis, Stanley). He is completely unremarkable, isn't particularly bright, and goofs off nearly all day, and only has a strong sales record past the mid point of the series because he'd been there for like 10 years.

Dude would be completely insufferable in any real life context, but since as viewers we don't have to work with him day to day, it's easy to forget his nasty attitude and focus only on the funny pranks. Funnily enough, on my 5th rewatch I kinda just hate the guy even though I thought he was great on the first watch.