Correct me if i'm wrong, but the reason that jets and rockets don't look so much like a teardrop at the rear is also because this is where the exhaust gasses come out, and therefore there is no need to streamline for less turbulence.
Example here being the SR-71 - Look at the rear appendage which tapers off like a teardrop, versus the tips of the engines ( and yes the SR-71 is pointy because it goes Mach 3 . Commercial jets have rounded 'blunt ' fronts because they do not break the sound barrier. )
But then, note how the Space Shuttle has a blunt front.
Makes it all confusing doesn't it ?