A few oil change fails I`ve done:
One time I forgot to put the drain bolt back in and as I was pouring the brand new oil into the engine,I suddenly hear all this splashing,and I`m thinking,"Huh????????",and I suddenly realize all this new oil is pouring straight into the drain pan!
Another time,I didn`t pay attention when I`d removed the old oil filter (gasket came off and stayed on the oil filter tree). I started her up after re-filling the engine to back her off the ramps,and as soon as the engine started,I heard this shotgun sound,and the new oil filter had shot off like a bullet! I was like,"Woah!!!!!".
The last "oops!" I did......I`d finished the oil change,and decided to have a couple of coldies to relax a bit before backing my car down off the ramps,picking up my tools,etc. After my brews,I decided to go ahead and back my car down. I guess I was feeling REALLY mellow and had my head up someplace it shouldn`t have been and had forgotten I still had the oil drain pan under the car. Well,I back down off the ramps and ended up dragging my oil drain pan down the driveway,and it was stuck under the car,haha! I had to drive it back up the ramps to retrieve it!