Renting a car in Europe is easy as most of the posts convey.

Returning a car in another country (or even city) comes with a high premium.

Unmentioned surprisingly, is that many older European cities have "no fly" zones, large areas of the central city in which private cars may not be driven. In most cities there are only 3 parking places in any block and 4 cars driving aound that block searching for them.

Rural driving is pleasant and rewarding, although for the inexperienced high speed autoroutes can be daunting.