So, random story:
I played some TF2 yesterday for the first time in like forever. There were about 6-8 people in the server, 2 of whom where nQa guys. We all agreed to do melee only, which was cool, but after about 2 or 3 kills, one of the nQa guys would start using other stuff, like uber charges, jarate, sentries, flare guns, etc. I'd ask them to stop and just do melee only, like we agreed. They went back to normal kills for about 3 min or so before they started adding "extracurriculars" again.
Events like this are why I've never enjoyed playing with any of the nQa guys. They don't break the rules, and they don't grief, but they don't have good sportsmanship. It's just not fun to play with them.