I think none of u guys knew the answer so u started talking about planets!
If the beer glass and the table both had very low friction properties, the glass would continue to spin without starting to wobble. The smoother the surfaces, the longer it will continue to spin in a stable manner. Of course in reality, both surfaces have lots of irregularities. Apply some movement and you will find that small changes in the quality of the spin become magnified the longer it spins.
There is also another factor at play. The person doing the spinning won't be able to apply a perfectly uniform rotation to the beer glass. Again, small imbalances magnify as the kinetic energy applies itself to the object continuously during the spin.
