Particle effects from other players... OFF PLEASE.
When the game was being shown for the first times at tradeshows there was a colored aura around your target instead of the current circle at their feet.
It allowed for perfect visibility even through massive clouds of visual effects and was also working underwater (since the circle around the feet cannot work underwater there is no way to tell your target from the rest of a group currently, and that is annoying).
Some people whined about it ruining their visual experience, that they simply didn’t like it and now Anet chose to use the more mainstream circles around the feet.
I hope these people now understand what the aura was for…