Your experience is typical. Wildlife in wilderness areas such as the Clackamas District are exceedingly shy. But if you stay quiet for a long period of time, you'll see something. It's usually when you least expect it. I try to make a lot of noise, especially when hiking alone. Don't want to surprise a critter twice my size...I do tend to see a lot of deer, chipmonks, jays, and other common critters.
My wife bought me a bell, but it's too damn loud and makes me feel like an idjut. I just talk to myself alot, make weird sounds, etc. every once in a while.
As far as safety, use common sense. And make sure you tell someone or leave directions to where yer going. I know of someone that was stalked by a pair of young cougars, but that experience seems to be atypical. For the most part, animals want nothing to do with us humans. Top of the food chain and all that.