What does “you should mention that” on this context?

Question

I am watching and learning the Thor’s Ragnarok movie and in the beginning of the movie

Thor: I thought my father killed you, half a million years ago?

Surtur: I cannot die, not until I fulfil my destiny and lay waste to your home.

Thor: It’s funny you should mention that, because I’ve been having these terrible dreams of late; Asgard's in flames ...

So my question to you is: Thor used - "it is funny you should mention this". To me, it sounds more logical as "it is funny you mentioned this" rather than "you should mention this". Why was it expressed with "should"?

Answer 1

This answer from English Language and Usage may help: https://english.stackexchange.com/questions/206005/should-its-funny-you-should-say-that

It is an example of the "putative should" (https://www.thoughtco.com/putative-should-grammar-1691554) which is used in contexts expressing surprise in clauses following "that".

I'm not sure that the putative should is ever strictly necessary, or that it conveys any significant additional meaning. It is a matter of nuance. As far as I can tell it is a quirk of English, particularly popular in British English. It conveys no sense of obligation or command at all (as you might expect when someone is told they "should" do something usually).