Recently I went on an out-of-state camping trip with an old friend. Several others joined. The scale and location were intense and required everyone to pitch in. No problem, sign me up. My friend is super handy and became a bottle neck in many of the camp projects. Because of this I agreed to drive his son back home to mom (a 3-hour drive) mid-trip so that he could attend the first week of school. This was always part of the plan. Me taking him (rather than dad) would allow dad to stay and work on projects. I had no car there so I used my friend's truck, a vehicle I had no prior experience with. On return I filled up with gas (pumped my own, not in Oregon). Didn't make it far because the truck took diesel and I put in regular. I apologized to my friend and spent several days in town dealing with the mess. The tow, hotel and first round of repairs cost $5,500. I paid. There remains a final bill and the task of getting the truck back to my friend, who lives in a different state than me. (He car-pooled home at the end of the trip when the repairs were still unfinished.) While I initially felt it was right to take full responsibility, I am now getting resentful over the high cost for (what seems?) a pretty understandable error. I WISH my friend had told me it was diesel! (He agrees that he did not.) This information was not indicated anywhere on the truck. The gas cap cover had been painted from diesel-signaling green to matte black. Any thoughts? Am I just resisting the idea that I f-ed up? Or does my friend share some of the responsibility?