You'd have to list the things I've been fired up about. Almost by definition, if the things I'm no longer fired up about, I've forgotten that I ever really was fired up about it, but the things I'm most likely to remember are precisely those things that still raise a certain amount of passion with me.
Things I know I'm still 'fired up' about...
1) Killing the print editions of Dragon and Dungeon.
2) Completely dissing their own past products in their marketing of 4e. Related note, completely dissing the fans of their past products (anyone remember 'Cloudwatching'?)
3) Printing a 4e of a game which is utterly incompatible with the prior three editions of the game to the extent that is fundamentally a different game.
4) The ludicrous statements of some 4e defenders concerning what 4e would be like - I remember alot of arguments about how great the Skill Challenge system was going to be - and the absolute faith that they had in a product they'd never seen.
It was going to be out of the box a rules light, stream-lined, flexible, narrativist, minature optional system with very fast but still cinematic combat resolution but that also made resolving complex situations with skills as natural and as important as combat, and if you didn't believe that then you were a mental defective. And the skill challenge system was going to let you use any skill at any time, and it was going to make everyone in the party to contribute all the time to everything, and if you couldn't see the beauty of the coming system you shouldn't disagree with the people that did, because you hadn't seen the rules. If there was anything which you didn't understand from the previews, that was ok because it was going to be the best written edition of D&D ever with the most compelling fluff, the best DM advice, and in fact the DM advice would be impossible for anyone to read the rulebooks and be a bad DM or design a bad encounter. Because of course, there are no past issues that were the result of bad DMing, because everyone knows a good game system can't be run badly. And the rules would be such that it would prevent rules lawyers from being pricks. And the math would be fixed so that everything would just work with no need for DM input, because the designers said so. And the modules were going to be the best ever written for D&D ever, so that you'd totally forget about all that badwrongfun of earlier editions, which let's face it, sucked. And, it was also at the same time going to change nothing about how you played D&D because it was going to be the same game, and an even smaller change than between 3e and 2e, and heck, even if it didn't support playing D&D the same way then that was ok because D&D was always badwrongfun anyway.
5) The entirely pointless and contridictory new alignment non-system, and the other trashing of old fluff just for the sake of trashing it.