attacking or scouting with their base with your units and then forgetting about them as you build something . Happened all the time in my extreme nub days
I was playing with friend, and he convinced me to share vision. It waqsa like this "c'mon lets share vision for fun, you first then me" So i shared vision and he didnt.I was defeated
Hmm one of my Worst moves was Reaver dropping my partners base and destroying all 4 Nexuses. He left 10 seconds after the first base died. I felt so bad for him but it also felt so good having to backstab. :o
LOL we were all noobs at 1 time, but the most noobiest thing tht i love is when idiots on the other team ( zerg players) save themselves by makin a hachtery in their teammates base. the creep expands like nuts n they cant builld shit.
My most noobish move would probably be when i was playing for the second time and i made my front door unbreakable but the enemy used overlord drops to kill my mineral line and then my tech bulidings and the path back to my base was so congested that my troops marched in one my one and where murdered... LOL