The idea with quicksand was that you would keep sinking in it until you drown (imagine it as a bottomless pit). So pushing down on it would only get you stuck f

The idea with quicksand was that you would keep sinking in it until you drown (imagine it as a bottomless pit). So pushing down on it would only get you stuck further. Pulling on your bootstraps would do nothing because by pulling on them you would need to push down elsewhere and thus still continue to sink. In reality you can't drown in quicksand because it's more dense than the human body. To avoid getting stuck it's entirely sufficient to just move slowly to loosen it and break the suction as with mud. Pulling on your bootstraps is useful to free your boots but entirely unnecessary to simply free yourself. But this expression refers to escaping the fictional trope, not the real thing.