That rather takes the whole meaning right out of "challenge".
Is that any less of a challenge compared to when you actually want to play a game of bowling and people are leaving the game after they hit 30 points or get a strike?
I keep right on playing when then do that, trying to better my personal best score.
Here are the challenges I find easy.
Bowling: Get 30 points.
Pottermore Charms: Complete 3 levels.
Ice Break: Complete level 1.
I find that pool is difficult considering if your friends are busy, it's hard to find a game with some who keeps leaving.
For the pool game it is best to have a friend play with you.
I was playing someone I had never met and he quit on my just before I won so that I lost .
He called me a "shark" because I was doing rather well and was winning. I explained to him that I was just trying to go the challenges and he told me he was as well, but didn't want to play someone he considered a "shark".
I guess that was the best for him because after quitting like that, he certainly had no hope in Hades of winning a game against me.
His loss really.