
You know what, if you ever want
to talk to me about a PROBLEM
The Big Bang Theory Season 5, Episode 7

that's the PROBLEM.
The Big Bang Theory Season 5, Episode 15

I'm starting to remember
the PROBLEM with
The Big Bang Theory Season 7, Episode 21

Well, the only PROBLEM was, he had no,
what you call, fissionable materials.
The Big Bang Theory Season 1, Episode 4

...for a restatement of
the quantum measurement PROBLEM.
The Big Bang Theory Season 3, Episode 13