@Breffni-Potter
I have self-admittedly EXTREMELY high standards for what I define as "snappy", and it's a plague that prevents me from using some software ( like some popular IDEs ) because they just can't keep up w/ the pace at which I need to be able to stream code from my fingertips to feel fully productive. Basically I hate waiting for anything small. A new tab to open, one to close, code hinting to process and render, a file list read, a web page to serve and render. Things like boot up or shut down time don't matter to me, because those are one-offs when you're not trying to accomplish something granular. App load times also don't matter, though typically the faster those are the faster the overall "snappyness" will be. It's a quirk, but I think there are a lot of people like me, in fact I've seen a lot of people blow up on smaller scales when their computers aren't responsive. I also feel like I have an exaggerated ability to perceive latency, for example most people I've talked to can't feel that command + tab on OS X is slightly, but palpably slower than alt + tab on Windows ( probably because they have a programmed animation that has an exact, while superficial duration before the stuff is fully faded and at its final static position ). Stuff like that bothers me. The old OS X fullscreen animation used to make me homicidal. It's faster now ( as of El Capitan ), but still obnoxiously longer than it should be. So to answer your question, snappyness is achieved when I don't feel like I'm waiting on an interface to deploy my next keystroke or click, or in more abstract terms, "when a computer can mostly keep up with me". There is not a single mac on the market today, even a $4,000 Mac Pro, that consistently can. End rant.