Can'tcun Fyre Festival was the worst top event I can remember, it was like a slapstick comedy.
Otherwise, events where there are so many walkovers and retirements in the final stages that the tournament becomes a complete joke. I once went to Eastbourne and it was semis, and one semi involving La Woz was a walkover and the other was a retirement, so they had to put on a scratch exhibition doubles to give people something to see. That is probably the worst that I have seen live, also seven games of Seles v Schultz McCarthy before rain stopped play all day.
The night matches at RG this year were a low, many were feeble and one sided. One was over so quick, there was still a non night match on Lenglen or Simonne Mathieu that was still going on when it finished.