I hate some of the oil filler caps used on newer vehicles. They are usually too small or so deep down in the engine bay that you spill half the oil you're trying to put in. One of my favorites is the cap and filler found on my '04 Ram 1500 5.7L Hemi. It's huge!

 I don't need a funnel to add a quart of oil and it's actually sealed better than many of the newer fill caps I've seen. I wish more auto manufactures used a filler cap assembly like this. Now if I could somehow keep oil from spilling all over the suspension and steering when I remove the oil filter, I'd be golden.