Easy question but it may be relevant to which hemisphere you live in, do you wear foot wear on the SUP? Obviously if it's ice and snow on the water but what about here is Aus, crocs, thongs ( foot wear not underwear ) sandles, etc etc. do you do it for comfort on long paddles or when you are near a reef, interested to know!
I use these if I am surfing over rocks or paddling the muddy river.
Over the last 6 months I have chopped all the straps off and removed the elastic draw string around the ankle. No more pins and needles in the feet 
and comfy like slippers.
www.surffcs.com/collections/travel-series
I use a set of quiksilver booties every time for 2 reasons: the tops of my feet don't get sunburnt and you get so much more grip on the deck. You can easily hold the board over near 45 degrees and your feet don't slide off. I reckon it helps heaps and don't fall off as much. Never surf without them!!
Booties for better grip and protection from rocks and sea urchins and stuff, and walking over hot sand on 40+ degree days. 
I prefer a mid-height boot because you can seal it snug around your ankle. That stops sand getting in when you're walking into the water. In a shore break you need to lift your feet off the bottom to stop the sand getting blasted into the shoes.
Avoid a low cut ankle because there is nothing more painful then getting sand and broken shells between your toes inside a boot. Of course that doesn't apply if you don't walk over deep dry sand.
Select to expand quoteSandsy1 said..
What a bunch of pussies. Bare Feat you knuckleheads!!!!
I was waiting for this comment,lol
Nice to get a few options here some of which I was wondering about so thanks guys!
I wear low top booties for all shallow water touring after cutting my big toe open on some sort of shell. Went to the doctors for some stitches and they got all paranoid about infection, so I ended up with two days off work with my feet up (but not in a good way). It's much more fun to be barefoot, but IMO it's not worth the hassle of getting cut.
surf barefoot tho.
HB
My feet cramp when the weather gets cooler. So, I wear a wetsuit sock, made for wearing with fins, 2mil. Because of the sock like construction, they are easy to turn inside out to dry.
Ditto re YT's recommendation.
I thought they looked ridiculous before trying them after losing a big toe nail and now feel naked without them.
