I guess this sounds obvious,... Anyway, you would think it is. Be aware of your battery levels, and the wind. Youtube is full of videos taken by people who literally plunge toward the water just seconds from land, because they want to get back exactly at zero percent. One guy wound up on a sand bar and had to get a boat to rescue his phantom. You can see another stumbling through surf over rocks to get his. I don't know why people are determined to use every last bit of range to track down freighters, or sailboats, or a rock way out at sea, but with just a light offshore breeze you can see them sweating bullets trying to make it back.
You can't land short when you fly out over water.
Oh, yeah. Don't trust the sensors on the bottom over water, either. Forgot that one.