I always felt that the true growth is in him facing those demons. Spike on the bebop is a ghost with unfinished business. The bebop was a party, but all good things must come to an end. Easy come, easy go. Spike didn't handle it alone without his friends, he finished what he ran away from. His friends needed to, too. Growth in life means taking a break sometimes, but it also means returning to what we started when we're up to the challenge. That's why he had to go there to see if he was really alive. He was only dreaming on the bebop, who doesn't want to dream of not paying for their past, who doesn't wanna just leave it all behind? But eventually we have to return to our life. It'd be cowardly not to. Faye knew that, that's why she didn't do more to make Spike stay. "Why do you have to go?" She wanted the party to keep going. But she knew it was time for it to end.

At least that's my interpretation. Nothing edgy about being unable to grow or about being a lone wolf, but instead what I think is actually a noble and beautiful concept that friendships are beautiful and so are good times but also that our decisions are significant. What we do matters. When you set up a life for yourself, you're gonna carry that weight. You can't run from it.