
It's an amazing COINCIDENCE.
Can we leave it at that?
The Big Bang Theory Season 3, Episode 3

also my way is
a happy COINCIDENCE.
The Big Bang Theory Season 5, Episode 19

What a COINCIDENCE.
It's the future Mrs. Wolowitz.
The Big Bang Theory Season 2, Episode 7

Oh, what a COINCIDENCE.
You can discuss that with him...
The Big Bang Theory Season 3, Episode 5

were identical by COINCIDENCE,
The Big Bang Theory Season 5, Episode 14