In most first world countries? Sure (even though it isn't what it used to be, but it would still be a nicer severance than expected if you're ready to spend a lot of money in legal fee or have an union providing you a lawyer).

But I guess that in the US not thanking your boss for letting you work is a valid reason to get fired

I don't think so. If your boss tells you to cut it out and you don't cut it out, that's firing for cause. You might think it's a first amendment thing, but that only protects you from the government telling you to cut it out