I found the reason my fridge slide is tight, and I bet others are the same. On the right side of the fridge slide, next to the fixed top, there is a "look good" trim, that runs the full length. I stripped it off after finding I couldn't get the blade of a very thin plasterer's spatula down between the slide and the fixed top. It turned out to be that piece of trim. Bingo.... the fridge slide now is as smooth and free as my Black Widow drawers in our Triton ute.