How do you pull yourself from depression that has lasted for years?
Depends on what's causing the depression. If it's genuinely a medical thing (ie "in your head") and not based on anything other than chems in your body, then meds/therapy is the way to go. If it's caused by your situation, then you have to change your situation. If you can't change your situation, change what you can and leave the rest.
How do you find something you enjoy and do it, when you enjoy pretty much nothing down to the taste of food?
There's usually something someone enjoys, no matter how badly they feel. There's usually a teeny sliver of something. For some people, it's just harder to find it. For a horse person, maybe it's riding related, or training related, or just going for a walk in the woods with your horse in hand. If you're down enough, you won't get that big surge of happiness, but you might instead feel a little less 'blah' or maybe a hint of 'meh'. Anything over "this sucks" is a good thing and grab it when you can get it.
How do you avoid the depressing situation when it's literally unavoidable, and will be for the next several years?
You change what you can of it, and just accept the rest. I don't know what the situation is you have in mind, so I cannot be more specific. If you can't change anything, then you prepare yourself for when it does in the indirect ways you can. For example, if you knew you couldn't own a horse for several years, then you might want to do the best you can to become an educated horsewoman, a better rider, etc.
How do you "calm down" and "not worry so much" when there's nothing BUT the worry?
Again I don't know your specifics, so I'm going to be general and vague. You find what you CAN have an effect on, and deal with that. Whatever you cannot alter or affect, you shrug and stop worrying about it. Simply because worrying does nothing to help the situation, and accepting that is how you deal with it.
How do you live in a world that values the appearance instead of the reality? Deception versus truth? Lies versus integrity?
You mean this world? One day at a time.
And if there is a greater being, or even KARMA, why do so many bad things happen to good people? Do evil, hateful people ever get a comeuppance for the evil they inflict upon others?
I don't believe in "karma" or a "greater being". Things happen. Sometimes they're "good" things and sometimes they're "bad" things. Sometimes they happen to people who don't deserve it, sometimes they do. Life is not fair. There is not a system of checks and balances. If you wait long enough, something bad will happen to a good person, and something good will happen to a bad person, and vice versa.
You cannot sit and seethe, waiting for some invisible force to come take pity on you and exact revenge. How does that make you a better person to be wishing ill on someone anyway? How does it make your life better to cling to the hate?
You can point to something bad that happens to a bad person and go "HAH That was because you're BAD", but was it really? Or was it just because that's how things played out?
If you can't control it or affect it, you let it go.
And mind you, I am a firm believer in an eye for an eye and an ear too for the inconvenience.
Lastly, and slightly separate, how do the most hateful of individuals, those who spew the most intolerant vitriol....appear to the world as "righteous"?
Righteousness, good and evil are all subjective. Those people ARE righteous, in their own circle. But what's good to you, or me isn't necessarily good to someone else. Good and evil are labels we assign to things in order to have civilized society.
How do you guys deal with the garbage in life when it just keeps coming?
One pile at a time.