We like green cars, and we define the term loosely. Sure, the 2010 Toyota Prius is green. But so's the 2009 Chevrolet Silverado Hybrid pickup truck, because a full-size truck that gets 20 miles per gallon is much easier on the planet when you need a pickup truck.

But try as we might, there are a handful of cars we've just never quite made our peace with. So returning from our Fourth of July holiday, we send you into high summer with five of our least favorite green cars:

(1) 2009 Smart ForTwo. We really, really loved the idea of the Smart. Until we drove one.

Its negligible length, astoundingly spacious cabin, and cool street presence are almost entirely negated by the awful pitching ride that the five-speed "automatic manual" transmission produces as it slams through its gears when driven energetically, pitching the car back and forth on its short wheelbase.

That aside, the Smart is usable around town--and the ease of parking this tiny two-seater just can't be beat. But on the highway, the 70-horse, 1.0-liter three-cylinder engine is severely underpowered. We've seen Smarts on Interstates; we wouldn't want to try it.

  • Rating: On TheCarConnection.com, we rated the ForTwo at just 6 points out of 10.
  • Gas Mileage: The EPA rates it at 33 mpg city / 41 mpg highway. But would you want to use it on the highway?

Mini E electric vehicle

Mini E electric vehicle

(2)  Mini E. This one may not be quite fair; the Mini E isn't a production car. A limited run of 500 all-electric Minis is being leased to drivers in select California and northeast markets for one year only, to accumulate data on how real live people use electric vehicles.

But on our test drive of the Mini E, we were crushed at how unpleasant it was. The acceleration lag negated the benefit of electric drive--instant torque from 0 rpm--and the violently abrupt regenerative braking truly shocked us.

We hope suggestions that our test vehicle had pre-release software are correct, and we plan to re-test the Mini E soon. We really want to like the car,  but as we wrote at the time, Rarely have we been in a car less ready for primetime.

  • Rating: It's not a production car for sale, so TheCarConnection.com didn't rate it--but we'd give it no more than 6 out of 10.
  • Gas Mileage: Infinite!

2009 Chevrolet Cobalt

2009 Chevrolet Cobalt

(3) 2009 Chevrolet Cobalt. They sold well during the gas-price runup of 2007, but we don't know anyone who owns one and we only see them in rental fleets.

Chevrolet is slowly replenishing its line with stylish, high-quality, economical vehicles now (consider the very good midsize 2009 Chevrolet Malibu, for instance). The 2009 Cobalt ain't one of 'em. The interior is grim, the seats are uncomfortable, the steering is vague, and the engine is noisy.

To be fair, the Cobalt is on its last legs. It will be replaced next year by the vastly superior 2011 Chevrolet Cruze.  But plenty of cars get better scores at the same age (it was new for 2005, replacing the ancient Chevrolet Cavalier). OK for rentals, not for our garage.

  • Rating: On TheCarConnection.com, we rated the Cobalt a barely passable 6.8 out of 10.
  • Gas Mileage: One high note: The EPA rates the base Cobalt at 25 mpg city / 37 mpg highway. Is it worth it?

2007 Dodge Caliber 4dr HB FWD exterior front upper left

2007 Dodge Caliber 4dr HB FWD exterior front upper left

(4) 2009 Dodge Caliber. Oh, the horror. We will do anything to avoid one of these in the rental fleets. At least its predecessor, the ancient Dodge Omni, had friendly styling.

The Caliber ladles faux-butch Dodge-truck styling onto a truly subpar economy car. After 10 miles or so, our first thought was that it was might have been a suitable competitor for a 1994 Hyundai, but was trounced by any current Honda, Toyota, or Nissan.

Where to start? Noisy engine that nonetheless delivers marginal performance, an astoundingly loud continuously-variable transmission (CVT), unimpressive gas mileage, and hard, nasty, ugly plastics inside.

Any good points? Ummmm...the seats are comfortable.

  • Rating: On TheCarConnection.com, we rated the 2008 Dodge Caliber at 7 out of 10.
  • Gas Mileage: Official EPA estimates range from a mediocre 24 mpg city /29 mpg highway with the 1.8-liter engine all the way down to 21 mpg city / 24 mpg highway for the hot-rod R/T model with a 2.4-liter turbocharged engine and all-wheel drive.

2009 BMW X5 xDrive 35d

2009 BMW X5 xDrive 35d

(5) 2009 BMW X5 xDrive 35d diesel. We kinda don't get the big, heavy SUV thing; we're station wagon people. So while we've politely ignored the gasoline-guzzling variations of the X5, we were hopeful for the new 265-horsepower, 3.0-liter twin-turbo clean-diesel variation (and, yes, that's its full, correct model name above).

But the same engine that's so delightful in the 2009 BMW 335d sedan has noticeable a throttle lag in the X5; it just doesn't feel good. What are they smoking in the tuning department in Munich?

The culprit may be weight; the diesel BMW 3-Series sedan weighs 3,825 pounds, while the X5 is a porcine 5,225 pounds. Just getting that mass to move requires different tuning--but it's nowhere near as nice for the driver. Disappointing.

  • Rating: On TheCarConnection.com, we rated the 2009 BMW X5 (the entire line, not just the diesel) at 8.4 points out of 10.
  • Gas Mileage: The EPA ratings are 19 mpg city / 26 mpg highway, far better than even the best gasoline X5.

Gas gauge

Gas gauge

[Headline appropriated from TreeHugger with thanks]