Look up retrograde and prograde, Rich
You're talking about retrograde orbits ! The Earth rotates to the East thus we usually launch in that direction, it saves a lot of energy.
If your flight is to Mars it makes a big difference in how much energy you need at liftoff and if you're planning to visit ISS going the opposite direction of it's orbit is of no use!
--Chris Vancil
PS this is something I learned if fifth grade!