Solitude makes me insane. Yes, I am more productive, but I also become highly unstable. It's a tradeoff. At the end of the day, I value my mental wellbeing more than my productivity. But good friends are hard to find, and I'd rather be alone than put up with the wrong people.
Edit: Now I really feel like reading Nietzsche again.
I relate to this. I like the way you make it clear that given a choice between sanity and productivity, you choose the former. But is this not a false dichotomy, I wonder? I hope!
For me, prolonged absence of close company quickly begins to feel like low-grade depression ... or general melancholy. I used to enjoy solitude, but the years and the birth of my children has shifted most of the time I used to crave for myself. I don't crave solitude as badly anymore. In fact I fear being left alone. Also our recent financial set backs and a few deaths in the family has left me questioning the idea of being productive entirely.
The funny thing is that I'm not entirely honest when I get the company I crave ... I begin to display fickle emotions of wanting solitude immediately because I feel I'm not productive.
I'm really in purgatory right now with exactly that: sanity vs productivity.
Edit: Now I really feel like reading Nietzsche again.