If you are running low on gas, in the middle of the summer, in triple-digit heat, don't forget to fill up before stopping at home to pick something up.
I just walked 2 miles round trip in 103 degree F heat (that's something like 41 degrees celsius). With a gas can. Naturally, the way back with the full gas can was all uphill.
Crap, I can't stop shaking. Must replace electrolytes. Gasp.