Forgot something essential on a camping trip

[Alan]

I left the tent poles at home once, I had all the tent parts except the actual poles. Had to rig something with sticks and rope. It looked ridiculous but it worked. What essential item have you forgotten that ruined or almost ruined a trip?

 

[Cpt Jon]

Oof, been there! I once forgot the camp stove and ended up eating cold beans straight from the can