There’s no equivalent to the British concept of ‘proper’ in the US. It’s the adjective you use to describe something that’s correct against the implicit standard, as in a proper cup of tea, or a proper job. The funny thing is, it’s not the same as good, or enjoyable, instead it just implies that the subject complies with the natural order of the universe, as if beverages or careers had some platonic ideal they could be measured against.
What I love about this country is we get to set our own standards, there isn’t some cultural ether that everything’s defined in reference to. Most people I knew in the UK sneered at gaudy holiday house decorations, but I secretly loved them. Now I can decorate my house with multi-colored Christmas lights, and people respect that it’s my business, rather than trying to force me to conform. If anybody has an issue, it’s treated as a matter debate between us, and doesn’t rely on an appeal to some faceless ‘proper’ standard of behavior.
I have a lot more fun now I’m leading an improper life!