I often feel the same - I certainly don't drive anything exotic or overly powerful; a bog standard BMW 335d with circa 300bhp and around 6s 0-60 time.
At the NSL it doesn't feel much different to doing 1/2 that speed. I find that to really open it up, you have to be doing stupid speeds for UK roads - though the 425 ftlbs can put a smile on my face every now and again.
The car that I had the most "fun" driving was, dare I day it, an MX5 that I owned a couple of years ago.