By the time you have snowboard pants and layers on, and things in your pockets - maybe a transceiver strapped to you... You tend to need bigger than you think.
I have a burton (well Analog) size L (@5'8 165). I thought I should have bought a M when I first tried it on (over a t-shirt and jeans). I thought I should have bought an XL when I came back from my trip.
We are all atheists about most of the gods that societies have ever believed in. Some of us just go one god further.