I've owned a couple pair of the Classic Crocs and found them amongst the most comfortable shoes I've ever owned - while the tread is unworn. As it wears, it becomes more slippery when wet. I bought the Bistro Clog because its sole solves the possible hazard. However, this pair is the first non-vented Croc I've gotten. I found, when wearing the shoe indoors exclusively,  that I had water build up from body heat. I needed to dry the shoes twice during the time I wore them. I was wearing socks for medical reasons, and the wicking of the fabric became an issue. I'll never get an unvented Croc again. However, the main reason I write is about the fact that the two shoes were NOT the same size. The opening to the left foot was a full 1/4 inch larger than the right foot. Sitting side by side they looked like two different sizes - which of course they weren't as they are molded. It is the opening that is a quarter inch different - which in my case makes the foot slide too much. I assume each foot is molded from a different mold. I'm not clear how that great a variation can happen, but it is enough to make the left &#34;too large&#34; for me as it produces too sloppy a fit. Crocs are made in different places. These say &#34;made in Vietnam&#34;. The Classics I'm wearing as I write this were made in Mexico; they're fine and fit well, but they have the traditional sole that becomes very slippery in time - not so safe for these old bones.