I have been trying to master it over the last few weeks, as we begin to tame our garden. But I think we must have a wild mattock rather than a domesticated one.
There is presumably a knack to subduing it. There is presumably a way of ensuring that the adze bit of it makes contact with the same section of shrub on each wallop, so that you sever the branch/trunk/root rather than just create a series of impressions up and down it. (Mind you, I would consider it progress if I could hit the same shrub.)
Alas, there is no Mattocks for Dummies. There is no masterclass to attend. There is not even a Cubs mattock proficiency badge to strive towards. It’s just a battle of wills. And the mattock is currently winning.
So if you see me wielding a big metal wallopy thing-on-a-stick, it may be best to maintain a safe distance.