I heard this one from a friend (?) of mine, Ryan Sexsmith.

A man is driving along in the Irish countryside, when he comes
upon a gas station. Now, since hes in need of gasolene, the
man decides to stop. He says to the attendant at the station,
Fill it up, will you? The man says, Sorry – were fresh out
of gasolene. So the man considers, and says, Well, Im still a
bit low on oil, would you mind topping that off? And the
attendant responds Sorry, but no oil either. The man thinks,
and asks the attendant to wash his window, to which he gets the
by-now predictable response that he cant do that. The man at this
point is fairly mad, so he asks the attendant Just what kind of
gas station is this? The attendant then looks both ways, and very
carefully whispers to the man To tell you the truth, its an IRA
front.

The man then says, Well, in that case, you can blow up the tyres!