Personally I have never had more fun than farming the same opponent over and over again with reaper because they refuse to change their tactics because they think its the only tactic that works, like two bastions in the corner of the dojo who you wraith behind intangible and blow them away or a pharah who keeps flying up to the rocketship hanging from the ceiling and rocketting my team thinking no one can get up there even though I went up there seven times and cleared her out every single time.