It’s an interesting language phenomenon that I observed between the German and English language. The first time I heard someone say in the US that bad things come in Threes I was surprised and appalled, given that in my home country, Germany, we say the opposite.
I wouldn’t go so far as interpreting a generally positive vs. negative attitude towards life into such a statement, but it is certainly interesting.
A probably unrelated, but noteworthy observation in this context is that many people in the US seem to be of the opinion or expectation that work has to suck. I had never gotten that impression back home.