He said something like: "You know what's confusing? AD&D First Edition."
I said: That's blasphemy! How dare you besmirch the holy words of the Great Gygax! I excommunicate you from ever joining the ranks of the OSR! Tremble before me and despair!
Actually, I thought about it, shrugged my shoulders and could see his point.
The AD&D Player's Handbook only contained rules for the character classes, spells, and some advice. It doesn't even show you any methods of how to generate ability scores--that's in the Dungeon Master's Guide. Oh? You want secondary skills? Dungeon Master's Guide.
Combat Tables? The table for Turning Undead? Saving Throw charts? Dungeon Master's Guide. Unless you were adapting rules from Basic D&D, you needed the DMG to run combat.
After the Player's Handbook debuted in June of 1978, Don Turnbull said gave it a 10 out of 10. He said, "whereas the original rules are ambiguous and muddled, the Handbook is a detailed and coherent game-system and very sophisticated." What?
Several years ago I did run a short-lived AD&D campaign. It was fun, but most of the players couldn't stand not having access to all of the rules. I tried using Thac0, but that confused some of them, so I just used the tables in DMG. But even then, for some reason, they subtracted their combat bonus from their "to hit" number.
"No," I said. "Don't do that. Because you don't know when you'll get a penalty. Just stick with the original numbers."
Each time somebody leveled up, it was kind of a chore, because I had the DMG and had to tell them their combat modifiers and new saving throws.
Eventually the campaign ended with a hilarious case of intra-party killing. (Which I might share some other time here on d20 Dark Ages).
After that experience I could see why old school players just used the Basic rules as starting point and cherry picked stuff from AD&D.
Yet in defense of AD&D: somehow it worked.
People were still buying the AD&D Player's Handbook after Second Edition came out--leading to print runs through 1990.