Happy GM's Day!
I'm a Game Master and I'm going to tell you some of my secrets:
I get nervous before every session I run. 20 Years after the first time I ran a game, it still happens.
I love being a GM because I like telling stories, but I love becoming NPC's more. I love making up gestures and catchphrases and unusual behaviors.
I like that moment when everything seems to click and the group's mind's eye is all watching the same scene. Those are the moments I live for as a GM.
I've grown to enjoy World Design, but it's a skill I'm still exploring.
I'm far more comfortable being improvisational than having a strict outline for the evening. I make a rough road map, but we could end up anywhere before the night's over, and that's ok.
I have to consciously choose focusing on the game, instead of the rules. I'm a game designer by instinct, but I've discovered that it's more fun for the groups I've played with to simply play, than to let myself fret over the rules.
As I get older, I want faster character creation and straight forward rules. That's why I dove into the OSR.
My greatest enemy is Game Master ADD.