I'd like to suggest a different reason for the likely judgement: You didn't see the obvious (in his view) sign for the fitting rooms.

Neither of you has to be 100% wrong in the situation. Just because he spends up 40 hours a week seeing that sign and 100% thinks it is GLARINGLY obvious doesn't mean you 100% didn't even try looking for the sign and possibly distracted him from a (perceived) important task to make up for your laziness.

It's a balance. You can both be 50% objectively correct or any variation of levels. The sign could have been higher or lower or a different look than you were used to AND you only glanced around and didn't really stop to look.

I know for a fact that I've been on both sides of this kind of scenario. Would bet most could find one of each in their lives, too. So it's a learning experience, remember that what is obvious/simple for one person (you/someone else) isn't obvious to another person (someone else/you) and try to act accordingly.

But the fart comment is very insightful, you know?