I don’t get why people shit on Vaan’s lack of shirt because there are much more egregious lack of shirts way before you even see him.
I just figured he saw someone else do it, thought it looked cool, then failed miserably at replicating the look. And Penelo eventually just got tired of calling him out on it.
Considering most men in Rabanastre don’t seem to wear shirts or wear the minimum amount of fabric required to count as a shirt honestly Vaan’s just fitting in with the fashion of the nation.