It sucks. In my life, I've only met a handful of people who have deep and extreme mental resonance and chemistry (less than ten, sadly zero of who I have any kind of physical relationship with right now; I don't mean romantically but any kind). Physical attraction I find very common (there are a loooot of really physically beautiful people out there, holy smokes), and essence ("soul/spirit") resonance is also not uncommon - the number of people who happen to be an essence that is a soulmate must be in the millions, by my count [I have a kind of unorthodox understanding of what 'soulmate' means]. Both combined, also not that uncommon. But real mental resonance that is profound, amazing, mutual, and has that electric "it" factor is so rare, at least for me. And if that's not there, the other two tend to fall by the wayside. A lot of people are really awesome, friendly, have things in common, have that "it" factor partially, etc, yet somehow it just doesn't click in all the right ways, mutually, and it ends up being... somehow lacking experientially on my end. I'm not trying to invalidate them at all, but... I wish I would meet more people who fall into the third category -- a lot more. Feeling lonelier around others than when I'm by myself is messed up.