I find fishing alone, and hunting alone for that matter, to be some of the most intimate and rewarding experiences.
It is just you, or you and the dogs, against nature. If you succeed, it's your success. If you fail, it's your failure -- but hopefully with knowledge gained on what to do next time in order to succeed.
A buddy can't claim a duck as theirs, or show you up with more fish. And he can't use up all the bait or wreck your gear. If it happens, it's on you and nobody else.
Then again, selfie photos with hog C&R fish are pretty difficult. If you catch a fish of a lifetime and nobody was there, did you really catch it? Plus, unloading and loading a boat solo in less than ideal conditions can be frustrating and sometimes dangerous. It's nice to have a buddy there to hold the boat while you park the rig.
I've witnessed some pretty spectacular fog-draped sunrises and glass-still waters by myself, and wished someone was there to see it, too. But there is no greater pride then zipping back to the dock with a livewell full of fish you caught yourself.
I guess I cherish both experiences. There are times and places for fishing with friends and going it alone.