It's because you see them as a cashier or a server, instead of a person working as a cashier or server. There was some period of 6 months where for some reason

It's because you see them as a cashier or a server, instead of a person working as a cashier or server. There was some period of 6 months where for some reason (I believe it was cause I was living overseas for 2 years in a country without my native language, then returning back to where I could finally talk again) I was very outgoing and talkative. It was glorious and I happily talked with everyone. Would crack jokes at people as I passed them by on the street. Unfortunately Philly beat the reserved "heads down" scowl I was used to back into me.