I walked into Gucci in my jammies once and every SA present rushed to my side.

I know I definitely wasn't
dressed up but I guess it wasn't that casual either ..? Or maybe they're just polite. I'm hoping it's the latter because all SA's should be courteous regardless of your socio-economic standing, how you are dressed and
especially your body size. Although I am 00, P, XXS, or 38 for Italian sizing, but I've almost always been treated well.
That same day though, I walked into LV and got treated horribly. I made a point to drop my wallet while exiting and let everything slip out though.

Their loss.
I also went to Prada, YSL, Bally, DKNY, Burberry and Bvlgari afterwards and everyone there was very kind. That LV instant did piss me off though.