It’s the biggest day of your relationship so far. For if her parents don’t like you, chances are she won’t like you for much longer either. Unfortunately, this is one of those social situations that calls for the ever-ambiguous smart/casual. So jeans are ok, as long they’re not ripped. Soft shoes are ok, as long as they’re not scuffed-up trainers. T-shirts, however are never acceptable.
You see, meeting the parents is about impressing upon them how you embody the 3 Rs: respectability, responsibility and reliability, and a shirt collar will subconsciously remind them of that nice young chap that works at the bank who they had always secretly hoped their daughter would fall for. Just steer clear of any loud colours – that generation was far too familiar with Liberace to forgive anything other than a white or pale blue.