
Intimacy in any form
has been CHALLENGING for me,
The Big Bang Theory Season 9, Episode 11

- Just as CHALLENGING as you?
- Yeah...
The Big Bang Theory Season 10, Episode 5

but the truth is,
Amy is just as CHALLENGING.
The Big Bang Theory Season 10, Episode 5

I know what a CHALLENGING man he could be,
The Big Bang Theory Season 9, Episode 14

The guy's a genius. Maybe you weren't
CHALLENGING enough for him.
The Big Bang Theory Season 6, Episode 6