the small little branches that break my paintballs before they hit the intended targets. the cool guys who use 3 round burst, full auto with their guns using about as much or more paint than the speedballers on an airball field without really hitting anyone.
Stand off. You get both sides hide and when they decide to push forward both teams are too nervous to move up so they spend 10 minutes taking pop shots at each other. then when you try to move up solo you are instantly the focus of the other team and its often times a suicide rush.
i think this is the biggest problem with new players.
poison ivy, oak, or sumac. I can deal with the stalemates on the field, uneven teams, and all the other minor annoyances. it sucks running through a field and paying attention to the game and then a week later have poison ivy popup everywhere
This and when you have a good shot and your marker quits.