Pogo's 27th Birthday Celebration event

If you play on 'easy', it only takes about 40 seconds per game.  Count another 20 seconds to transition between games and it's about a minute for every 5 trophies.  It takes 17 five-trophy games to hit that 85.  I got that one done in under 20 minutes, and that included a bathroom break.  

They're taking advantage in other ways, like the ongoing Merge Academy saga.  People are paying to play games that they actually can't play.  If your progress doesn't save, then it's not worth playing.  However, it came in handy for the Birthday Event because with nothing being saved and progress resetting, I was able to make those 700 merges in about 5 minutes.  I merged 100 or so items, left the game, then went back in to a total reset.  Nothing saved, nothing taken, but the merges counted. 

The worst one, in my opinion, is the Soliaire Home Story challenge.  120 streaks will take me days.  I only got to 19/120 and I'm done for the day.