For millions of Americans going into the back country is at least an annual ritual for hunting, camping, fishing or just hiking. An encounter with a black bear is much more common and black bear attacks are much more common than a mountain lion encounter.
Bear attacks are much more prevalent two times a year-in the spring and fall when bears are looking for food. Bears are not going to sneak up on you. If they see you they will either turn around and leave or come charging at you. While they are fast they make no attempt to hide from you.
Mountain lions on the other hand use much different tactics than bears. Mountain lions can get up to 120 pounds or so. Mountain lions stalk their prey and frequently can be upon a victim before they know it using stealth and speed.
There's two ways to fight off an attacking mountain lion. The first is to use bear pepper spray that creates a wall of mist between you and the attacking animal. They have extremely sensitive noses much like bears. When they walk into the pepper spray they will turn around and run.
The second technique is to appear as big as you possibly can. Stick out your arms. If you're wearing a coat spread the coat out as big as you can. Find anything nearby that you can throw at the animal.