Most refrigerator lights are protected so you can't break them by knocking against them with something hard. Nevertheless, unusual accidents have a way of happening, and you may regret trying to fit that oversized pan onto the top shelf. You can also occasionally break a bulb when trying to replace it. Once you have cleaned up the shards of broken glass, though, getting the old bulb out isn't difficult.
Unplug the refrigerator. If it is hard-wired into the house circuitry, turn off the circuit breaker that controls it.
Clean the food out of the refrigerator and set it aside. Vacuum the insides to remove any shards of broken glass from the shattered bulb. Wearing protective leather gloves, chip off any shards remaining around the metal base of the bulb.
Insert a pair of needle-nose pliers into the centre of the base. Spread the handles to force the sides of the pliers against the base, then turn the pliers counterclockwise. The base should turn with them. If the base jams against the socket, turn back clockwise to release it, and then turn counterclockwise again.
Insert a small slot screwdriver between the base and the socket, and bend the base into the centre. Grip the bent metal with needle-nose pliers and turn the base gently counterclockwise. If you meet resistance, turn back the other way and then forward again. In this way, you should be able to work the base out without breaking the socket.
If the base isn't stuck with corrosion, you may be able to use the potato method. Cut a raw potato in half, push the flat side of one half against the base until the metal digs in. Turn the potato counterclockwise, and the base should turn with it.
If you forget to turn off the power to the refrigerator, touching the base with pliers, a screwdriver or your bare hands can give you an uncomfortable, and possibly dangerous, shock.