Notice the word choice here: "memorable," not "best."
Memorable, meaning that one event that stands out most in your mind (think Rorschach test for your entire season). Could be good, bad, scary, hilarious. Could be a run, a day, a person, an after-party. Just wondering what stands out after nearly another season has come and gone.
For me: Vail on a Monday morning after a fresh dump in January. Myself and a friend of a friend I'd never skied with (and really didn't know too well) got back to Blue Sky Basin around 9:30 a.m. to find it untouched. We lapped Skyline and Earl's Express for a solid hour before people started to fill in around us. Giddiness ensued. To make things even better, my new best friend absolutely shredded on his snowboard, much more so than the "friend" who bailed on me last minute to sleep off another hangover.
New ski-buds, especially ones who can hang, ones who show up on time, ones that pop for beers afterwords and never bitch about a single thing, on days like this, are especially priceless.