Rocket/jet-powered everything.
Started off thinking of a jet powered bike, because it would be fast, and batman-like, but hard to control, noisy, would drink fuel and burn the paint off other vehicles and any pedestrians that got too close (and probably your own leathers), which isn't good.
But... why not everything?
Cars, of course, which can be awesome in a variety of ways but are always non-starters in reality, from the batmobile to the turbine car prototypes of the 60s.
Chainsaws. Hoo boy. Can you imagine the stuff you could cut through when every tooth on the chain alternates with a link that has an integrated rocket motor?
Washing machines. Ponder that a moment. ROCKET POWERED WASHING MACHINE. Your clothes have never been more cleaner. Or stretched. Or on fire.
Hamsters. As if the little buggers aren't fast enough already, now they do 300mph and have the power of flight. But maybe they can be trained to go shopping for you, bringing each apple back one at a time, but superquick?
Shoes. Aw yeah. ROCKET BOOTS. Click your heels together, and suddenly you're flying. Can you feel that? Can you feel each of your legs being pulled in opposite directions with a few hundred pounds of thrust each? Or your whole body starting to spin at a thousand rpm?
Televisions. I'm not even sure how that works, but it's definitely awesome. Jet powered TV. I'm not talking about in-flight movies either.
Aeroplanes. They go real fast and can carry lots of stuff, but they need super long runways miles from anywhere.
...oh, wait, that one's real. Moving on.