“That sucks” is negativity. “That sucks, here’s why, and here’s how to fix it” is criticism, ​ Someone with an informed, critical opinion is, in my experience, far less likely to be negative than someone not as informed. If anything, critical thinking adds dimension to an appreciation of the world around you.

Here’s the thing: the hero is the most damaging person on a team, particularly on a team that’s supposed to be writing high-availability or otherwise mission-critical software. ​ The hero is a human patch. ​ When a team can rely on a hero, they don’t need to grow and learn collectively. They don’t need to get better. They can coast along, which serves no one in the end. ​ You’re clearly managing someone highly motivated, but you need to shape that motivation into something more constructive.