It's effing hot out. Drink some water.
If you don't, you'll wind up fucking up an otherwise hilarious scene that you're shooting because your body temperature will suddenly sky rocket, your vision will go blurry, your hearing will sound weird, and you will have to get on all fours to prevent yourself from passing out. This happened to me today. Kinda scary. Not fun.
Skipping breakfast was probably not a good idea, either.
But how else am I supposed to stay skinny???