A couple years ago I saw another cyclist with a broken chain and since my multi-tool had one of those chain de-riveting or whatever you call it tools, between the two of us we were able to fix his chain. Another time I was stopped at a gas station gulping down a Dr Pepper when a rider dressed in full lycra and on a beautiful new bike came up to me and asked if I knew anything about these new fangled valve stems, (Presta.) I had one of those little brass valve adapters that I showed him how to use. The moral of both stories is that you don't have to be an ace mechanic to be able to offer assistance.