As a Reinhardt main, I love to charge head-first into the enemy team, pin one person, kill another with a firestrike, and then cry as my shield gets melted by a Bastion as I await my impending doom.
As a Moira main I like to laugh as I slowly kill anyone that isn't a tank.
As a D'va main I like to watch as the slow moving heroes run away when I ult at the center of the map.
As a Junkrat main, I love to fight a pharah in the sky and land a head shot and kill her. Also love to leave traps randomly and then get a kill. And setting up traps and bombs and successfully killing them all. feels real good.
As a junk main, I like to put a mine and trap in front of the enemy's spawn door, even if it's comp. (Also don't hate on me for being a junk main, I honestly don't play overwatch that much anymore, it hasn't been on high on my list of priorities)