Why do I enjoy being sad?

Prolonged melancholy is a natural for a pity party.

Maybe you don't enjoy being sad. When we're depressed we get depressed about the bad aspects of the past because they scar us, and the good aspects of the past because they meant something to us and now they're gone and it makes you sad because you long for it, you miss feeling it, nostalgia fulfills us and tricks us into thinking we felt exactly that feeling as the time we relate it to. Nostalgia exaggerates what really happened. We remember good things better than they happened and bad things as worse than they happened sometimes.

I like being on my own too because I find it impossible to trust others. So instead of becoming aggravated with social interactions I isolate. It might not be the best solution but it seems to work.