junglers are the ones that start the fire that makes laners troll
in some cases the laners need a jungler to get kills and towers. and the jungler may have not done the jungle or pay attention to what he does as jungler. in return you have laners that sit at their side jungle or at their tower for the rest of the game/ ive seen junglers at masters that do the whole jungle while their team is already taking the inhibitor towers. i find junglers to be the unsportsman of all the roles require the most moderation