Is it normal to throw rocks at things?

So, a few times every week, as a hobby, I like to collect rocks from my garden, stand in the middle of my street, and throw them at people's mailboxes. The houses in my neighbourhood are fairly close together, so it gives me a lot of targets to hit. I'm a really good shot too, I hit them every time with a lot of force, often either smashing the mailboxes or knocking them over. I just love to do it! It's so much fun! I've done it over fifty times, even after my neighbours keep replacing their mailboxes or fixing them. One neighbour came to my door one day and starting going insane at me for doing it and yelling about how he hated it. Is it really that bad? It might be annoying to some people, but it's a lot of fun for me.

I also love the sound of when the rock smashes into the mailboxes.

Is this normal?