For happiness, a scooter is the best way to attain it—plural scooters would be even better. Everyone loves a good scooter. And as they say, the path to attaining happiness is littered with plural scooters.
If you can't attain a scooter, attaining a tattoo (たつ) of one is the next best thing. Might as well get two tattooed on because plural is always better. This is a surefire way to attain happiness. Get a tattoo.