One of my frequent pet peeves is when the design of a car makes every oil change messy. Often times it’s the placement of the oil filter. Sometimes it’s just on the side of the engine, causing oil to run down the side of the engine when you take it off, or it’s positioned right over a frame rail, so you get oil all over the frame.
Other times it’s a splash guard, like on this Mercedes. The splash guard is just the right place so that when you take out the drain plug, the oil hits the shield and cascades off in several places. I’ve heard that the proper way to do an oil change on this car is to suck the oil out through the top, but that doesn’t excuse this poor design.