By the way, do the teachers on here provide cultural advice too?
Yes, but IME a lot of the 'cultural advice' given by Polish teachers is based on an idealized idea of what the UK was like about 50 years ago or typical Polish cliches about the US.
Native speakers do too but will tend to contradict each other. A lot of the cultural advice I'd give (as an American) won't help them in the UK much (and vice versa).
Generally, a negative approach works better as a teacher with some understanding of Polish ways can give broad advice about things that are okay in Poland but not in the US (or UK IME). These things change over time as well though. Some years ago you'd have to mention that it's not a good idea to ask someone how much they paid for something or how much money they made (perfectly polite in Poland then though much less common now).
One problem that's still probably around is that Polish conversation is a lot more freewheeling and personal than anything most English speakers are used to. Delving into topics like religon, politics, sexual attitudes, relations between ethnic groups/races etc. happens far earlier in Poland. Polish people will usually find the bland, step on eggshells nature of English conversation (between people who don't know each other well) to be kind of boring.