Many times on the trail it is going to be a little muddy where you want to sit.
The solution is a sit pad.
My first was half a zlite. That is seven ounces. Win and I each had one (and we both gave them away).
A sit pad from Thermarest from a hiker box was next, that was two ounces. While smaller than the half a zlite it is kind of heavy and bulky —not to mention thirty dollars.
Next is the current half ounce iteration.
You can buy them one at a time for under a dollar or in bulk for less than $.75 each.
Soft. Flexible. Waterproof. Bright colors. Packs very small. Seems perfect for keeping my bottom dry while sitting down to eat dinner.