I can agree to it because I experienced it before.
I have 2 reasons before:
1. It's either I can't sleep because I am excited about how to spend my winnings

2. Or I can't sleep because my winnings are not enough and I am still willing to play more, bet more, and expect to grow those winnings.
The excitement of winning can not be overly emphasis for anyone who has had such experiences and will testify of course and this excitement can be on imaginary, and I completely agree with you, how funny it can be thinking your head out on what exactly the money will be use for, most times I will smile and decide that I will not touch the winning I mean it should have some rest and the urge of gambling more for more winning will also be there and this in most cases has landed majority of us in to lossing everything we have won and even more.