This is a bit true for me. I expended a lot of effort looking for a co-founder, even though it was not obviously true that a co-founder would help me with the particular project I was in. To a certain extent, it was Mark Suster's insistence that a co-founder is not necessary and you can just "go it alone" if you have the cojones/stamina that made me say f' it, I'm just going to do it on my own.

Actually, the breaking point was when the "co-founder" I found told me on the day after I arrived in Berlin to work on the project full time that he wouldn't be able to join in. In this case, he had a totally legit reason (his wife was in the hospital with cancer), but it was probably the case that aligning things as far as a "co-founder" was never necessary from the beginning. Either way, it was a bit catastrophic mentally for me for a couple weeks, toying with merging with a different startup in the same space instead of going full stop ahead on my own. Even now loneliness sometimes takes its toll.

Thankfully, in the end I spent a lot more time on product than worrying about finding a new co-founder, and we have a pretty d* good product now and 30% growth across our KPIs for the last two months. Not really a lot of cash in the bank account, but hell, this is Europe and investors like to sit on their money instead of invest it.