It could be that the oil was so new that it hadn't turned the darker color that comes from dirt and grime suspended in it. Either that, or you drained something other than the oil.
The drain plug is on the right hand side of the pan (facing the front of the car) and you can see creases in the pan funneling all the oil toward the drain plug hole. Once I got under the car, it was pretty obvious which one was the pan...it was the only thing that looked...pan shapped.
I replaced my old oil with Mobil 5000 and it was pretty clear when it went in...about 5 qts out, 5 qts in.
The not slippery comment makes me concerned though. The other thought I have is that the oil fill cap is pretty clearly labeled (something like "Use SAE 5W-30 oil only"). If you had drained something other than the oil, you wouldn't have had room for 5 more qts. (from the low to high mark on the dipstick is only 1 qt)