Let me tell you about my buddy Lucio Correia dos Santos. He makes cool music, he has a rad frog tattoo, he's in Overwatch, and he is the furthest thing possible from the usual grim-n-gritty shooter hero. For real: I'm used to hearing shooter characters belt out variants on "Let's kill those assholes!" or "Those assholes are killing us!", and the angriest thing Lucio can ever come up with is "I'm not hearing that noise!" I mean, his American accent doesn't make a ton of sense since he's from Brazil, but nobody's perfect. Lucio clearly takes joy in being able to help out his teammates, probably because it's a nice break from his career as an international music icon.
Most characters in shooter games are career soldiers, desperate folks driven to violence by forces beyond their control, or sociopaths who just love killing. Relatively few of Overwatch's colorful characters fit that mold, but Lucio may be the furthest from it. You'll find one great example in the Numbani map, where massive posters hang from the walls promoting his global concert series. Not to mention D.Va - the other celebrity-turned-hero - sometimes asks to trade autographs with him at the start of the match. Lucio knows he's got it good right now, and he wants to share that with the rest of his team.
Ok, with all that uplifting stuff out of the way, I have to be honest with you. I truly love Lucio because he is, in every way that matters, a Jet Set Radio character. He has roller blades and dyed dreadlocks, he can wall ride, and he dances around and listens to fat beats (Blizzard even released full versions of his healing and speed boost tracks). I start most matches as Lucio theoretically so I can help get my team to the objective in a hurry, but it's really just so I can wallride around the starting area while tossing up my Lucio-O's cereal spraypaint tag. Also so I can use his little music gun's toot attack to knock people off cliffs.
To be clear, I think all of Overwatch's heroes are pretty neat... with the possible exception of Reaper, a grown man who chants "Die! Die! Die!" while wearing a dumb Halloween costume (he is definitely the only person who thinks that knock-off Scream mask is cool). And I also play support roles in a lot of other multiplayer games. But none of them have ever made me quite as excited to help out my team as Lucio.