Clearly we have different definitions of 'formality'

Geekman: I think my talk at [conference] went pretty well. But I'm worried that it was maybe too informal.

Me: Informal talks are great! I much prefer to listen to someone talking about their research like a real live person than someone standing stiffly behind a lectern and reading off a script.

Geekman: Maybe... but all the same, next time I think I might wear shoes.