Is there an English idiom/expression for "a problem came from a place no one expected it from"?
As in "we were not even paying attention to this part, because it was supposed to be simple & reliable, yet it generated the most problem!"
There's an expression in my mother tongue (Russian) that goes "oh comes the trouble from where least expected", is there an English version of this?
I would say "out of the blue", but this just means "unexpected" without stressing the "unexpected origin" of it.
UPDATE: I probably phrased my question poorly. I don't just mean "unexpected trouble". I mean "we were EXPECTING trouble, but we were LOOKING THE WRONG WAY"
Best Answer
The problem came from left field
PS. I know this was originally a baseball metaphor, but we still use it in the UK where few of us understand or care about baseball!