I have to agree with the comments. Running games means I get to play all the time. If there is no game on I can world build. I'm used to playing at my time, when I want. I have a bigger time bank of play when I run.
There is a PC chee which is way different than the elan of well executed GM fiat (just being a good game master). I can't just snatch it up all the time. I'll define PC chee as inner listening, with moments of outward playing. No luxury of time. The game is on and time to be efficient with each touch of the ball. Is it harder or easier, Player or GM? Neither, both are worthy of pursuit towards fun and excellence. I've just done one more than another. Switching "roles" it shouldn't come as a surprise that the work is different enough a conscious transition is helpful when flipping. I probably have informal ways to make transitions.