I dislike working alone. This is despite the fact that I'm an introvert and really do appreciate my quiet and focus.
Part of this is that I really enjoy the camaraderie of having peers close at hand. From a personal standpoint, this is better for my mental well being, and my morale regarding the job in general.
The professional downsides of working alone are also significant. A team is a support structure. When you can't bring your A-game, they can compensate. Ironically, a team can also *facilitate* focus. When there are other folks involved, you don't need to be responsible for responding to every concern of the other people and teams you need to coordinate with.
More important than that, though, is feedback. A team keeps you honest, and keeps you moving forward. It's easy to stagnate working alone, only pushing forward when something bugs *you*. But a team is your first customer. You have an obligation and a commitment to do good work every day, because the team needs it. With a team, what you do matters between releases and under the surface, where the customer will never see.
A team makes you better than you need to be by yourself.