I'm not knowledgable about chemicals but I've done a lot of MDMA in the last 7 years and it seems like only very few batches are really good to roll alone with. It works, but I'd much rather go with a dose of lucy or 1.75g of shrooms for a nice solo experience.
To me, some molly seems to make me want to go to go to a concert and jam, other molly actually makes me extremely introspective. I can party and dance on any molly but very few batches have actually made me introspective on the level of lucy/shrooms, I wish I knew what makes some molly different than other batches.
So when I get one of those batches, I can easily do it alone. Otherwise, as others have said, I'm going to spend the entire night texting/calling friends and never being satisfied because I'll wish every person I'm calling was there with me because I'll be fucking bored. But give me a good introspective batch, and I can just enjoy some music and take some personal time to just sit in my own head and try to get perspective on stressful areas of my life that I've pushed to the back of my mind. When I was dealing with legal issues espicially this was a huge benefit. But very few batches I've tried in my life have qualified as molly I would do alone. Maybe, 5 or 6.
I would love to know what makes certain batches of molly make me want to blindly party while others make me think much more.