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I hate it when you don't play guitar for a while..
..then you get back into it and your fingertips start hurting, and of course, you have to stop fairly soon otherwise you get blisters and then you end up not being able to play for a day or two until your blisters piss off.
I thought about burning my fingertips a little to speed things up but I guess it is better to just wait for the hardening.