Weather. Unless it's part of an adventure, I only ever see general temperature (cold in the winter, hot in the summer) mentioned. No rain, no hail, so high winds, no snow. Storms only happen at sea, apparently.
Food. I've had characters hang on to the same week's worth of rations for 12+ levels. I know why this is so; I did play in a game where we marked off a day of rations every game day, and it made for tedious bookkeeping.
Equipment distribution on the body. Just because you have a 22 Strength doesn't mean you have room to hang two swords, a morning star, a long bow, and a half dozen daggers on your person. I run into this challenge a lot, since I tend to draw the characters in my games. As someone who goes to Ren Faires in full garb (costume), including sword, I can attest to how much encumberance a single medium weapon is, much less 2-4.