why should you not hit two hammers together?

Question

I’ve heard that saying countless times and no amount of googling gave me a satisfactory answer.

In: 8838

Answer 1

Because hammers are hardened metal, it makes them incredibly strong against bending and warping, but also very brittle, so if you hit two hammers together, they can shatter and send metal shards flying, which I’m sure you can imagine can be incredibly dangerous.