Haha, ok maybe not 7krpm, but 4krpm is a daily thing. This is why i love my 335i - i can just push the throttle and be off with no drama or noise, or i can rev it high for maximum smiles-per-gallon.
A lot of people do grow out of this and just want a car that's more sensible, that does good MPG, but there are many many people who don't and still love the howling noise of an engine as much at aged 50 in their Porsche 911, as they did aged 18 in their Ford Fiesta. I have a feeling i will be one of these people.
Enjoying fast cars with nice sounding engines and using revs isn't a sign of immaturity or childishness as you may (or may not?) be suggesting it is, it's something is addictive, exciting and grin inducing.