[cuddlybacon]

> But we don't have the same cultural concern against underthinking. I have never heard someone telling their employee or friend "you're underthinking this". Surely overthinking is bad, but when underthinking can be severely dangerous, it's easy to see why some people overthink.

We do this all the time. We just don't use the word "underthink". "You didn't think this through." "It sounds like you haven't gotten to the details yet." "Are you sure that's how it works?" "You need to start thinking things through." "You have a brain. Use it." "Pull your head out your ass." I think all of those phrases are suggesting the same thing underthink would.

[xyzelement]

I think that's exactly right.

If you run into traffic and get hit by a car, the conversation is about that, not "under thinking" because the impact is painful and obvious.

However, it's more subtle for someone to notice that it takes you 30 minutes to cross the street because you're way too cautious, and the impact of that ("you could be doing a lot more with your life than standing here") is less obvious.

[TapWaterBandit]

To add to this:

- Look before you leap. - Measure twice, cut once. - Stay silent and have people think you're a fool, open your mouth and confirm it.

I'm sure there are many more common idioms pointing towards the idea of "think before you act".

[jyriand]

Where I'm from we have similar sayings:

- Don't dive head first into water.

- Measure nine times, cut once.

And a random saying I just remembered: "Autumn has the eyes of a summer and the teeth of a wolf."

Edit:formatting

[shadowfox]

Err. What does that last one mean?

[tomasdore]

Maybe that:

- being late (acting in "autumn") ...looks/feels similar to

- being on time (seizing the moment at the right point, in "summer")

...but has a nasty bite?

[tonyedgecombe]

The trouble is those phrases are all quite hostile whereas telling someone they are overthinking can't be construed to mean "your stupid".

[shrikant]

Giggling at the irony of telling someone "your stupid".

[harry8]

"This may be more important that it at first seems."