Mental, in this case, is more or less the act of getting mad or going insane, and yes I think we’re all guilty of going “mental” with our kids.
I don’t know if it’s a bad thing persae, as long as you dont lose control. Once you’ve lost control then bad things tend to happen.
Another thing to note; people don’t make you mental, you become mental by your own thoughts and actions.
There is a level at which you can control all of your emotions and reactions.
No one can control them but you.