Congratulations! That's the point of a lease, after all, right? You get to jump around and try different cars... sometimes, as you said, very different!
Having fun in a car is a must for me. My 650xi GC hasn't yet arrived (should be here in a few more weeks), but if it's anything like my 550xi (and I'm pretty sure it will be), then it'll be a nice, large, somewhat boaty highway cruiser that brings amazing luxury together with fantastic styling, nice speed, and typical BMW build. But nimble? Corner carver? Sports car handling? Nope, nope, and nope.
Congrats on the M2 - that one should be a true blast to drive. And after 3 years, maybe you'll be looking for that luxury land yacht again!