Back in 2015 I had the bike shop give my Trek roadie a good once over. I took it home and tested it out in my neighborhood. Well something definitely wasn't right because the gears wouldn't shift. This was a difficult lesson to learn going uphill. I wound up falling off my bike and skinning my knee. 

I promptly took my bike back to the shop and they fixed the problem. Normally this would be no big deal except it was two days before I was scheduled to leave for my cross country bike tour. On the drive to San Diego and the first few days of the bike tour, the skinned knee was more of an annoyance than anything else. Thankfully we stopped at Jacumba Hot Springs a few days in and the healing waters at Jacumba Hot Springs did their job and a few days later the skinned knee was but a faded scar.