The biggest one was pouring wine. I remember a few times I poured it kind of off and I got that distinct look of class violation. Haggling about splitting checks also got those looks often, the lesson I learned there was that almost always, the party will want to split it evenly rather than do something as gauche as math, so rather than order less, order much more so you get a discount on your meal :-)

I also spent some time in a small rich beach town, and from that time I remember how my switching to boat shoes seemed to instantly ingratiate me with some people. Also never mention how "cool" it is that someone has a jetski or nice boat, those things were just taken as statements of fact.

To many people these might not seem like real mores or wealth signifiers. Maybe you think I was just over-sensitive. This whole article though, is about feelings, and certainly in those moments it seemed like everyone was certainly feeling something strongly.