honda designed the 6th gen accord so that you can just start it up and go - it says so in the instruction manual. but honestly, i just let it warm up for a minute or two and then i slowly pull out and cruise down the hill to warm up.

your car puts out the most exhaust when it's idling and also burns the most gas when it's cold, that's true. the higher idling RPM at the start is supposed to warm up the car until it gets to ample temperature and then everything runs fine and your VTEC will actually work (it won't work when the engine's just starting off too cold). just don't let your car idle too long. beyond intial warming stages, it's not good for it.