This isn't on Delta, it's on United, but you still will probably find some humor in it and I can't find a similar thread (too bad) in the UA forum.
He wore sandals on the plane, and took them off, to prop one bare foot on the FC seat in front of him. We were in the last row of FC.
I think it was karma (or maybe foot odor?), but the person seated in front of him reclined and straightened his seat maybe a dozen times during the flight. I've never seen someone so busy and apparently indecisive with the angle of their seat.
Thankfully, I didn't smell any feet.