I really want to be right. A novel concept I know. Last week I confused two different rule structures during my game session and it led to me making an ass of myself for fifteen minutes or so. Fifteen minutes of precious game time that none of us will ever get back.
My monster had 50% magic resistance and I was adamant that there was no chance for my player's 9th level Magic User (MU) to break through with his spells. This wasn't a misunderstanding of the rules regarding magic resistance, as clearly spelled out in the Monster Manual (p. 5-6). It wasn't me trying to save my monster. This was a confusion of the rules for the spell Dispel Magic and the math involved in that. I applied the Dispel Magic formula to Magic Resistance. I figured that it starts at 50%, then I added 10% to the difficulty as the MU was two levels under the arbitrary 11th level plateau, making it 60%. Then I added the monster's 50% resistance and came to over 100%. Very confused was I.
The worst part was that I was adamant about it and wouldn't let it go. One player thought I was making a new rule. Another was ready to give up and accept my confusion as the way things would be. Then another actually read the Monster Manual entry and my brick house came tumbling down. So certain was I.
I apologized to all of my players, more than that, I begged them to keep me honest and to help me in my efforts as DM. In the end I think I gained their respect as a person, if not as a DM.
Looking forward to this week's game!