I like to act toxic in League of Legends when I'm playing in a group.
Why would you want to be toxic?
I like to see if I can mess the other players up.
It's good to try and get an edge, but being toxic is bad. People will get mad and stop playing eventually. Try to find a better way to win.
It's not fun if they don't get mad.
Trying to spoil the game for all the other players by being nasty is poor sportsmanship and it makes the game not fun for them. Think of the other players having a good time in the game rather than your skewed version of fun.