The viscosity of the eye changes with age. Sometimes small clumps of cells get "stuck" in the eyeball. It's totally normal and happens to all of us. You can't actually see the "floater" per say, what you are actually seeing is the shadow of them as light moves thru your eye to your retina. Sometimes if mine are troublesome, I can "move" them by rapidly moving my eyes up and down (although it usually just makes me dizzy, and then I notice that more than the floaters.)
IF you have a BUNCH of them (and you will KNOW if it's a bunch, and not just a "new" one) that SUDDENLY appear, or if you have partial vision loss at the same time, THAT is a medical issue you need to get emergency assistance with.
Otherwise, they are just annoying things that happen when you are still on the sunny side of the dirt and still trudging along. Your brain DOES "ignore" them after a while, but looking a the bright blue sky, a bright snow-scape in the winter, or sometimes a bright PC monitor will make them "jump out" at you more.