"rage/sadness/pity/envy "
Pity ? for who ? them or yourself ? care to explain ?
It sounds like ( in some ways ) you envy the life they have ... try not to do it if it's possible.
They might have more problems than you but they are not gonna post it there,... so you might very well be in a better position than they are.
Anyway I think this episode hints that you could have some pent up aggression ... I wonder what really caused it.
To answer your question : No, violent behaviors are never positive. It's better to let out frustration in other ways ... have you tried writing down your thoughts ? talking about it with someone ?
( Some say doing regular physical activity or ( this may sound weird ) playing video games helps to get rid of problems ).
But of course going to therapy could be more effetive,it could help you understand what's the hidden reason of this anger and give you a key to unleash it without negative conseguences.
Before going nuts the next time, take a deep breath and try to evaluate if what you are going to do will actually be of help to your situation or not, it's a good way to avoid doing rushed and pointless things.
Stay cool buddy