It's become popular in recent years to say that the idea doesn't matter.
Or a way to stay on strangers couches, that just sounds terrible all around.
If you look at successful pivots, they almost always are a pivot into something that the founder wanted. Not a random made up idea.
One of the pieces of advice that we give at YC is: try to work together on a project rather than just doing an interview.
... We probably funded a rate of something like one out of ten solo teams.
Long term thinking is so rare anywhere, but especially in startups. This is a huge advantage if you do it.