Hybrids are an acquired taste with a definite learning curve, as I've found out. The first couple weeks, you need to be careful not to back over the family dog, or to let your new hybrid car motor away on you after you've exited. Much of the learning curve comes from remembering one simple fact: When a gasoline—or diesel-engine car is quiet, it's off. With a hybrid, silence could mean it's not running—or it is. And what happens next could make a funny story, incur property damage, brush someone out of the way, or run right over him or her.

Many hybrids (the ones that are selling in quantity) are strong hybrids, meaning they can run on electric power alone or in combination with the gasoline (or diesel) engine. (With mild hybrids, there's electric motor assist, but only when the combustion engine is running too.) With a strong hybrid, when you start off in your garage, or from a stoplight, often it's running on electric power alone, and it makes no noise except the minor squish of the tires. It would be nice if there was some audible indicator that was more declarative than a small, green Ready indicator in the instrument panel.

Some hybrids have a backup beeper, as on big trucks and backhoes, but on nearly every hybrid I've seen it's been turned off or was never enabled. I'd hate to see yet another law requiring backup pingers on hybrids, because nothing breeds more contempt for a do-gooder measure than making it a law. If you leave home early in the morning, the noise of a legislatively mandated pinger may wake people who are still sleeping, and you'd then need to pay a mechanic $50 to disable it.

Then, as you stop for your morning coffee, you silently glide into the parking space, quite often on battery power alone; you forget to put the transmission in park; and as you undo your seat belt, take your foot off the brake, and open the door, your hybrid might hesitate for just a moment—enough time to be more out of the car than in—and then start up on its own. Yes, there's a warning chime when you open the door, and the LCD panel flashes a "car in gear" message that is really aimed more at making sure the key is out so the battery pack is okay. But the chime is pretty polite and sounds just like the other warnings—say, for headlights on, key in ignition, or door ajar. This might be time to bring back voice prompts: "Danger, Will Robinson," or "Rolling!"

Some of the gearshifts are an acquired taste, particularly in the lovable poster child of hybrid cars, the Toyota Prius. When a transmission is electronically controlled, you don't need a strong lever. A tiny stub of a lever or a pushbutton is all you need. Prius has a stubby lever that comes out of the dash, which takes up little space (that's good). The shifter is in an H-pattern familiar to anyone who's used a manual gearbox. But once you press the shifter over and up into Drive, it pops back into the horizontal bar on the H, much like what happens when a manual transmission is out of gear. Except the car may still be in gear and ready to drive away. And with hybrids getting such great mileage, it might keep going for a couple hundred miles—or until it encounters something immovable.

Hybrids aren't alone in having return-to-center shifters: An increasing number of combustion engine cars have shift-by-wire electronic gear selectors that snap back to the midpoint. To put those vehicles in neutral, you have to push halfway down on the stalk, in the opposite direction. It takes practice.

Then there's the hybrid-car Star Wars display (if you have a center console LCD panel), that shows energy flowing into and out of the combustion engine, battery, front and rear electric motors, and generator (the electric motor running backwards), all with multi-colored arrows, plus a state-of-charge indicator for the storage batteries. It's overkill. Such complexity is unnecessary and serves mainly to impress you and then your neighbors with what a totally awesome friend-of-the-Earth car you have.

It reminds me of my fraternity brothers who had multiband graphic equalizers with dozens of flashing lights, hoping it would improve sound (it did, a little) and impress their dates (it didn't, a lot). Hybrid partisans have told me to show compassion and understand how much they want to maximize energy efficiency. Okay, I'll buy that, but you could accomplish much the same thing with a few green/yellow/red diodes or arrows that take up a tenth of the display.

Hybrid cars make an important contribution to the environment. Within five years, I believe the majority of cars will have some hybrid-like features: for instance, engines that shut down whenever you're stopped for more than a few seconds. In the meantime, if you buy a hybrid, prepare to deal with quirks.