Don’t poke the bear

On July 10, I posted about a synchronicity stream that began with running into Pythagoras on the Anonymous Conservative blog, and I ended with this paragraph:

My original intention was to slap together a quick post noting the almost too-boring-to-note coincidence of running into Pythagoras twice in a day -- but if you poke even a minor coincidence a bit, sometimes it explodes.

The next day, July 11, someone posting as Luke left this comment:

Perhaps instead of saying "Don't poke the bear" we should now say "Don't poke the coincidence".

Is “Don’t poke the bear” a common saying? I had never heard it before.

The following day, July 12, I again checked Anonymous Conservative as is my habit. Every post on that blog ends with “Spread r/K theory, because . . .,” with a different reason given every time. This time, it was “because you shouldn’t poke a Bear in the eye.”