We haven't had much new snow lately, so yesterday I finally pulled out my medium-width skis: 177cm Salomon Enduro 850's. I hadn't skied on this pair yet because they were new to me-- my original Enduros having been stolen off my car roof. I got this pair via e-Bay ($250), and they came with freshly applied wax.
But on the snow they felt horrible. Very different from my original pair. They were hard to control, and the tips and tail were grabby. Had they been put up for sale because they were a bum pair? Could they be extremely railed? I've never experienced that, but it was the only explanation I could think of.
Took 'em to the shop at the base area asking for them to be checked with a straight edge. The guy fingered the base and scowled. "What kind of wax is this?" he grumped.
Wax? I just wanted him to check the bottoms for flatness.
He scraped some wax with a fingernail and concluded that they had been coated with kick-and-glide cross country ski wax. He heavily scraped the bases and sent me back out.
I was dubious. It was too weird that anyone would put XC wax on alpine skis, and I couldn't imagine how improper wax could make the skis feel all wrong, especially at high speed.
But he was right. On the first run I effectively had my old Enduros back.
I understand now how different portions of each ski base must have been grabbing the snow at different moments. Grabbing the snow, then releasing, is what XC wax is designed to do.