Sunfish and Crappies love to hang out in think cover, especially around sunken logs. Getting hung up and breaking off tackle is a pain and one way to reduce your losses is to weaken your hooks.
By taking the temper out of your hooks you can pull your rig loose with relative ease. Once you're free, straighten the hook back out and get back to fishing.
Take a lighter or match and heat the hook up until it is "light red", cool it off and you're good to go. Weakening the hook in this manner will leave the hook strong enough for panfish yet weak enough to pull loose if you get hung up.