I stopped playing GE for that reason. I save GE for the DC, and then do as much as is left (or I feel like) at the end of the week.When they ask to win 4 or 7 fights without losing and you are high enough in GE to do that.
Definitely possible but I'd rather skip that one when in that conditions. Luckily without "-1" it will be no problem.
The only "challenge" that makes me skip a day immediately is the "waste x goods by dumping them in the treasury." It's not a challenge in the slightest, and the treasuries in each of my worlds already have 50,000 of each, at least, sitting there doing bugger all... I'm not going to waste more of them, so this particular task should be dropped for players past the point where those goods are actually useful for the treasury.