Mine is you run into them in the weirdest places. You could be running on a high kill streak and bam they kill you in the most odd places like a corner of the map or something!! I hate that
When you're playing headquarters and 3 noobs are rolling around the map in tanks 50 miles away hunting for ppl to kill. Leaving me and 2 other ppl to capture and defend the hq from 6 enemies.