Evil_Bob wants more cheese in his sandwich. He wants his cheese so bad he
will give it away if you let him, and
even if you don't, he will still give it away in a few days, so he will
just give it to somebody else. Bob wants cheese.

So he'll give away your cheese if you let him, and if you say no then
he'll give it away to somebody else. But the second he'll give it away,
you're fucked, because that's Bob's plan