I think it's because of the MDMA binges I had when I was younger. Maybe it's just some bad memories that trickers my brain and therefor keeping me from wanting to do MDMA. Because I really don't think I would get a hardcore shitty comedown if I used MDMA once in a while. It's all about moderation
Isn't everything? Moderation, and self control are two things you need to have (and money) if you want to use drugs and still function normally in society. Otherwise you're fuuuucked.