Are you sure its the wall? It could be the floor that’s canted. ;-) I noticed the same thing when a brother-in-law and I put in a tall cabinet in my mother-in-law’s kitchen. The top is further from the wall than the bottom is.
If you ground yourself before pumping the gas you’d be ok. I think if possible fire is really a risk, we’d never have had hot pit refueling in the Air Force I think.
That reminds me of a story I read in a Stars and Stripes issue way back in the mid 70s. where some couple were driving along and arguing about something when the husband stopped their car on a bridge, got out, went around to the passenger side and grabbed her purse and threw it over, then after a few seconds thought, got her out of the car, picked her up and threw her over after it.
https://www.youtube.com/watch?v=XW8iAVwt_Yc