[Tris]

My top choice, (apart from all of mine :-)) is the "Bob 3:17(am)" quote.

I really don't like "Något gick fel", as it's not actually anything to do with the game, and is an in joke that only some forumites and people who've found that error message have seen.

Even if people did enquire, the conversation might go:

Punter "Why does your t shirt say that on it?"

Tshirt wearer "It's from a quote that isn't meant to come up at all, which comes up when the game doesn't work"

Punter "and that's well known enough to be on a T-Shirt? Um....ok. I think I'll pass on buying that then"