so this conversation could take place:
English guy: Hey, what kind of flooring do you have in your flat?
American guy: Shag carpet.
English guy: yeah yeah...I hate carpet too.
Despite what others are saying, when I read it I interpreted it like, "fuck it [I hate the stuff]".
With what others have done in subsequent posts, you may have started what could be a new 'Games' thread: "Finish This Interchange" in which people provide an interchange where the last line is left off, and subsequent posters provide their own punch line for it.

Seems to me that could provide some things that would be pretty funny. You could, actually, start it with this set-up.
For this, my 'finished interchange' would be (to emphasize what your intent was, and to emphasize the sexual innuendo in addition):
English guy: Hey, what kind of flooring do you have in your flat?
American guy: Shag carpet!
English guy: yeah yeah... I agree with you: I went with hardwood, myself.