1) Getting your car stuck in the sand
Done that but did it so much before surfing that I knew how to get unstuck really well.
2) Putting your fins in wrong.
Never did that unless maybe you can put the right fin on the left side then maybe I have done that maybe still do that.
3) Walk of shame.
Nope
4) Mispronounce the name of a surf spot
Most likely maybe still do
5) Warm up shenanigans
Hmm I would say the author overestimates the value of a warm up. In my mind it depends on your activity level prior to surfing
6) Intoxicated ramble at a surf related event
Well I have been intoxicated surfing once so I guess so
7) Dropping in
Definitely done that. I probably will still do that again at some point
I am adding my own so feel free to add in

9) forgetting your board at the beach
10) forgetting to remove your cellphone from your pocket prior to getting in the ocean and also your glasses from your face