The longest I've waited is roughly one hour, for a table at one of the branches of Nandos near my home. For some reason, that place is busy every evening and every weekend. I don't see Nandos as being a restaurant worth waiting for, but I have a friend that won't eat anywhere else, so I waited for him

When I'm travelling for work, I'm usually in too much of a rush to wait more than a few minutes, so if there's a queue I'll go somewhere else.