I couldn't drive a Prius. I find it way too convenient to drive faster than 40mph on a regular basis.
I get stuck behind more slow moving Priui (plural?) than any other car!
There are some Prius drivers over the top trying to get 57, 58, etc.. MPG and they rarely ever step on the gas so I agree with you. It's maddening when they take 2 miles to get up to 45MPH so I won't argue with that point at all as I've seen it too many times myself.
I'd pull my hair out driving like that though, so I (maybe I'm a minority) have no problem driving it like a "normal" car. Granted, it won't have the pickup of a Mustang, but I've never had a problem with cars getting stuck behind me.
Each to their own. At this point in my life, spending significantly less money on gas is more important that spending a lot more money (both for the vehicle, the insurance and the gas) for the "fun" or "prestige" of driving something different.