It's not only not nice, it's a genuinely bad idea. If you have large sheets of glass (truck windows) and large heat differentials, you are asking for catastroph

It's not only not nice, it's a genuinely bad idea. If you have large sheets of glass (truck windows) and large heat differentials, you are asking for catastrophic failure due to uneven expansion. I know multiple people this has happened to personally, and there are also some truck manufacturers who recommend against this kind of defrosting for exactly this reason.