Are Smart cars always that crappy, or were the models used for Car2go particularly inferior? I'm not sure what the transmission was, but it wasn't a normal automatic - you could feel it go into neutral (losing power) and then engage at a higher gear.
It was crap.
(Not kidding, that's what Porsche uses, also F1 cars etc, last time I looked)
The mother-in-law also had one. Hers drove like crap, much like you're describing. It's annoying to ride with her no matter what she drives. We'd do the reset procedure on hers and it would behave a bit better for a couple weeks.
I suspect the computer would have a helluva time guessing what to do next if there's a different driver every day.
Traditional rental car services seem to have figured out how to make it work, why can't pay-by-the-minute places do the same? Something like demand-based pricing seems like it would work well for this.
I had the same problem when I was considering using Zipcar to visit Santa Cruz from San Francisco. I had no problem paying Zipcar's rate for the time it would take to travel. But Zipcar charges you for the time between when you take the car out of its designated parking spot and when you return it to the same designated parking spot, which completely defeats the purpose.
Though I can see how it would be less so if you only need to go from point a to b and not back to a.