When looking for extra long queen sized sheets, I'm disappointed to be redirected to extra long twin sized sheets. I would gladly buy extra long queen sized bed sheets so there would be enough material to accommodate my feet hanging off the end of my bed without untucking my sheets. I'm surprised at how little material is left to tuck under the mattress. To help mitigate this problem, I try sleeping diagonally to keep my feet on the bed, but that's not always feasible.
A queen sized bed is 80 inches long. If you leave a foot to move your head around without hitting your headboard or the wall, then you're left with 68 inches. So if you're over 5'8" (less than average male height in the US), your feet dangle at least partially off the end of your bed.