That's how many daily quests you can do each day, if you can manage it.
I did it.
I won't be doing it again.
This was an exercise to see how long it would take. The answer is: several hours. If it were not the weekend, I would not have managed at all. This won't be happening on weekdays. So I'll have to sort out what dailies I need to do each time I'm on from now on.
Sadly, there doesn't appear to be an achievement for completing all 25 in one day. Pity. I can't think of a more apt example of a more useless concept. An achievement that mocks achievements would be priceless.