I also immediately regarded this to be an American thing to do, and I am from the US, so I suppose I am guilty of the following. In any case, I find it slightly amusing that even when a (presumably) non-American does something that fits into this model of things Americans do, it can serve to reinforce the idea that it's an American thing to do. Is there a point at which this ceases to be so?
I think this is a very American thing to do. In most other cultures this is not true. Notably the OP is presumably British and my British grand parents most definitely were not "always selling" nor "putting their personality on display".