When it occurs once, it is __.

When it occurs twice, it probably is __.

When it occurs thrice, it is not __.

What is it?

Not a puzzle. Just a simple one.

  • $\begingroup$ I don't think this is a good question (since the answer is pretty much obvious, at least to me), but I also don't think it's primarily opinion-based, precisely because it has a single obvious solution ("mistake", as suggested by manshu, doesn't really work IMO). Voting to reopen. $\endgroup$ Sep 3, 2016 at 1:01
  • $\begingroup$ There's a single obvious solution, but it isn't really a very satisfactory solution: plenty of things could occur 3x and still be _____, and not everything that occurs only once is ______. And (especially in view of the "... three times is enemy action" quotation) it's a bit too straightforward: here are some well known properties of X, now find X. I didn't VTC but I don't think I'll VTR either. $\endgroup$
    – Gareth McCaughan
    Sep 3, 2016 at 19:04

2 Answers 2


Perhaps nikamed is thinking of




or something of the kind? (I don't find either a super-convincing answer, I have to say, but somehow the question gives the impression that there may not be a super-convincing answer...)

  • $\begingroup$ Here it is. Thanks for saving me from too broads. The coincidence was what I was thinking. $\endgroup$
    – newzad
    Sep 2, 2016 at 16:23
  • 3
    $\begingroup$ Good answer (+1), but I'd like to point out that things can happen by coincidence 3 times, and something that happens once isn't necessarily chance, so the question doesn't really work $\endgroup$ Sep 2, 2016 at 16:25
  • $\begingroup$ That's why I don't find it super-convincing :-). $\endgroup$
    – Gareth McCaughan
    Sep 2, 2016 at 16:33
  • 1
    $\begingroup$ Goldfinger: "Once is happenstance, twice is coincidence, three times is enemy action." $\endgroup$ Sep 2, 2016 at 16:57
  • $\begingroup$ @DanRussell Yes!! That was the one which I was trying to remember... $\endgroup$
    – Sid
    Sep 2, 2016 at 17:35

The clear answer is a



Mistakes can happen once or twice but not every time.

  • $\begingroup$ Not the answer I thought but +1 $\endgroup$
    – newzad
    Sep 2, 2016 at 16:16
  • 6
    $\begingroup$ @nikamed: This means your question is too broad. $\endgroup$
    – Deusovi
    Sep 2, 2016 at 16:18
  • $\begingroup$ @Deusovi I totally agree. $\endgroup$
    – manshu
    Sep 2, 2016 at 16:19
  • 1
    $\begingroup$ I don't think a mistake can't happen three times... Therefore I'm not sure if this is a valid answer and if it is really too broad. $\endgroup$
    – user14478
    Sep 2, 2016 at 16:20
  • 1
    $\begingroup$ Actually, it can ;) $\endgroup$
    – ABcDexter
    Sep 3, 2016 at 20:49

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