Forgive the heresy, but I've recently had some pizza delivered. I noticed it was quite oily, and I have seen and heard horror stories of pizza basically drowning in oil.
This does not happen when I make pizza myself, even with salami on top the amount of oil is small, and certainly not soaking through and through.
Is the oil added intentionally? Some (e.g. Asian) delivered foods are put in oil to keep them hot, but that does not seem to be a viable option for pizzas.