For some reason I thought that summoning helpers would reduce the rewards for beating bosses, so I soloed almost the entire game. It wasn’t until the black dragon in the DLC that I caved and summoned help. Later in Dark Souls 2 I found out this is not the case and it just increases the boss health.

I also soloed all of Demon’s Souls for a similar reason. I thought I could avoid invaders that way (its sort of true, but in that one using the item which allows summons also allows invasions). I had found out about world tendencies too and would avoid using those items thinking it would maintain an easier world tendency. Only after beating the game did I look this shit up and find out how it really works.