I took my mountain bike into Halfords as the chain had somehow got itself well and truly mangled after a nasty tumble. I asked if they could help, I'm sure that they must have wondered why I couldn't do it myself, but once they saw the extent of the mangling he said 'how on Earth did this get like this'. With all of their tools and with 2 people working on it for 20 minutes under my watchful eye (I really wanted to work out how to fix it if it happenned again), they got the thing back on and working properly. No moaning, just hard graft, determination, and on top of that they wouldn't take any payment for their trouble. I was really impressed for all the right reasons.