Had to have my windshield replaced today and my insurance paid for it and it didn't cost me anything. So long story short the kid installs the windshield and is very courteous and really did an awesome job. I thank him and gave him $20 and said to have lunch and a beer on me. My GF says I always seem to over tip or tip for services that I shouldn't. When someone does an exceptional job for me I like to toss them a few bucks extra. Thoughts??