I never talked much to people that use a lot of expressions, and the usage of Spanish terms, like “nada” or “amigo”, as I could observe from the outside, felt inconsistent. And upon thinking on that, it got me curious, is it common to use such expressions or not?
There’s a lot of very common ones that people don’t even think about. Mano a mano (often ‘mano y mano’ when anglophones say it), simpatico, and mi casa es su casa.