Really? I always thought Jim was one of the nicer guys in the show.
I can't remember the exact scene, but there was once Dwight was sad about his breakup with Angela, and Jim sat with him in the hallway consoling him. That's one of the nicest things he's done.
He also gave Michael first prize in the office-lympics, but I feel like being nice to Michael out of pity isn't a good condidate because... Michael is just such a kid. Lol