Remember that you are within your rights as a customer to say that you are not happy with the cut. In most cases the stylist should offer to cut the hair again to correct the style. On the other hand, you might not want to take the risk.
If your hair is long enough, try putting it up in a ponytail on bun. There are many ways of wearing a ponytail or bun without looking boring. Try using a headband, clips or other hair accessories to control wayward hair.
If you have a bob gone wrong, try adding some volume to break up the cut. Use curling tongs or a flat iron to create waves and curls that will disguise your cut.
For hair that has been cut too short overall, try styling products like gel, wax or hair pomade. Using your fingers, try making pixie-like spikes for an edgier look.
Above all else, don’t advertise a bad cut. Most people won’t notice unless you point it out.