Most of the time I leave work at work (because work consumes most of our free time, and I want my free time free lol). But, anyway, yes, after crazy shifts, sometimes I will think about the shift, too. How long have you been a nurse? I have been a nurse for almost 2 years (but less than 1 year in the ICU), and while I've been comfortable in the ICU even with the most acute patients now, I do think about work sometimes after crazy shifts. I never dread work like some do.
I think that as time goes on, we will stop caring about work when we get home. We care too much. This will go away after a few more years lol. It's crazy how I've become so much more distanced as time has gone on....I used to get teary eyed when a patient died, but now I don't (and it's not as if my patients die regularly lol). I empathize with patients/families always, compassionate, etc, but I don't really feel much emotion wise when a patient dies now other than, "Oh man, now it's time for post-mortem care, and this means I will get a new admission, which lessens the chance that I'll get out on time" lol, but I guess it's protective, too.