If you are going to beat on something with a thread on it undo the nut until it is flush with the end of the thread.
It gives you a bigger target and if you get lucky leaves the bits reusable.
The first time I powered up my grinder I ground a chunk out of my thumb tip
My dad ground a fair sized chunk out of his shin bone with a large angle grinder when it caught on the bolt he was grinding

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Things that are designed to do stuff to metal hardly even notice mere flesh and bone so treat them with the respect they deserve.
A light touch with a grinder and a bit of thought about which way is is pulling and where the sparks are going pays dividends.
The sparks look cool in movies but they ARE red hot and will stick to plastic ( UPVC window frames) lenses , paintwork the list is long.
Even if none of this applies there will be metal dust which will rust in an instant at the first rain.
This is not popular on concrete drives or anywhere else really.