I think sellers remorse hits most people. Selling always sounds good at the time, especially if it's to fund a new and exciting machine. The problem is that we miss what we're used to........and if it's been in the collection a while, then we notice the absence.
I sold my BSD (wasn't in great condition, but I loved it), and have missed it ever since. I go out of my way to play at mates places that have that machine just to satisfy the nostalgic itch. Would I ever own one again? Never say never, but with limited space, and so many other machines to enjoy, I highly doubt I will.