If you have a shirt with buttons, there are major decisions to be made. For example, pocket or no pocket, undershirt or no undershirt, sleeves rolled up or down, and how many buttons should you button. Let's walk through this one together.
Pocket or no pocket: whichever is clean(er). However, under no circumstances should you ever put anything in the pocket.
Undershirt or no undershirt: No undershirt, ever. Unless you're over 50, in which case: why are you reading my blog? Shouldn't you know this by now?
Sleeves rolled up or down: Up, always. Sleeves are just magnets for soppy beer mixtures on flip cup tables, and sails of wind resistance for beer pong throws.
How many buttons should you unbutton: Between 3 - 7. Stick with 3 if it is a conservative affair and 7 should be if you have a massive, but relatively hairless chest. You can substitute playing guitar for muscles in this/any scenario.
