I just got it (at age 30) for the first time and I'm not looking to lose it either.
Actually, I fall under the new three strikes you're out system we got since April 2002. This means that if you are taken off the road for any more serious offence (among which 'pushing', 'cutting' and 'severe speeding', for which the police takes you off the road) or causing an accident that involves injury or death, you get a strike. Three strikes, and you have to take both a theoretical and practical exam. Fail those, and you lose your licence completely, after which you'll have to start all over again and retake the real exams, at the relevant costs (right now 200 euro) and with the regular waiting for a bookable exam time (at least a month).
Of course, this measure goes beside the usual hefty tickets or even imprisonment you would get in these cases.
Like TwinTurboJay, I prefer to get my racing kicks out of Gran Turismo.

But I will and do occasionally test the car's accelleration fully when I drive the ramp to the freeway. There's no accelleration limit, after all, just a speed limit. The more I drive though, the less I"ll probably be doing that, because fuel isn't cheap ...
I adhere to the speed limit as best I can, but I don't mind testing the car a bit when the road is clear and the speed limit generous - i.e. it requires some decent handling to actually keep that limit.
Above I just formulated the issues, but normally I would just let a fast drive pass whenever I can do that safely and let him go drive himself off the road somewhere else (or get stuck in traffic just ahead, as is usually the case, where you'll often just catch up with him again). My driving teacher tends to be a little more 'instructive' to other drivers when we were on the road together, smashing angrily on the horn whenever people show some bad and therefore dangerous driving. He agrees with me that this almost never helps, but sometimes you will wake someone up to a danger that he'd otherwise not been aware of and can cause problems when he or she gets into a situation with another, less attentive driver. I think he has a point there.