2. There are few more reliable ways of making oneself feel better than by helping others feel better. It doesn't necessarily matter whether the others you're helping are people you actually know or hypothetical strangers you believe must be out there somewhere. If you succeed in reaching the latter, they'll become people you actually know.
3. It is possible for one flower in a backyard garden to make the difference in whether a pollinator species becomes extinct or not. It is possible for one or two or three backyard gardens to provide a corridor for a species that would otherwise be isolated on one tiny wilderness preserve to travel between multiple wilderness preserves and thus greatly expand its habitat. It is also possible for one person to make the difference in whether another person survives or not. It is possible to make a lot more difference in the world than you might think.
4. Feelings are a way of processing information. Thoughts are another way of processing information. They are interrelated; the thoughts you have can influence the feelings you have, and the feelings you have can influence the thoughts you have. For example, if you find reason to believe that a certain political belief is more reasonable than you previously thought, you will probably feel more liking for the people who hold it; or if you feel a particular fondness for one person who holds a certain political belief that you've previously considered unreasonable, your fondness for this person may make you more receptive to the idea that perhaps their political belief is less unreasonable than you've previously thought. Thus, neither your thoughts nor your feelings are random events inflicted upon you from outside; you have some control over them. On the other hand, your thoughts and your feelings are both valuable ways of processing information, so deciding to just stop processing information at all and to randomly start feeling perfectly okay about a terrible event is just as clear an indication of mental health problems as deciding to randomly start believing blue is orange and two equals three.
5. People in other countries are real people. Murdering them because you don't like the actions of their government is just as bad as someone murdering you because they don't like the actions of your government. Talking about their deaths in numerical statistics does not change the fact that each and every one of the thoundands who die dies as an individual human being with individual thoughts and feelings and is mourned by other individual human beings with individual thoughts and feelings, all of which are just as complex and intense as yours. Also, people who are different from you in any other way are also real people and also have real thoughts and feelings, even if their thoughts and feelings are ones you find baffling, dislikeable, or just plain wrong. Cruelty toward them is still cruelty.
6. You are a real person. Insulting yourself or physically mistreating yourself is just as bad as insulting someone else or physically mistreating someone else. Also, do you know how it feels to watch helplessly while someone verbally or physically abuses someone you love? That's how it feels to anyone who loves you when they have to watch helplessly while you verbally or physically abuse yourself.
7. No one can love you for who you are unless you tell them who you are. The way to tell them who you are is to actually tell them. Not to sit around thinking about maybe someday telling them. And also not to just tell them the easy parts and hold back the hard parts. The hard parts are the ones you actually most need to tell them.
8. What random strangers or people who are emotionally unimportant to you think of you does not have to matter at all to you unless those people pose some sort of actual physical danger to you. But how you behave toward them matters because that affects what you and the people who are emotionally important to you think of you.
9. Anytime you behave badly, even if nobody catches you at it, you add to the list of hard parts you'll have to tell someone later before you can be loved for everything you are. (And worse, you add to the list of recent hard parts, the parts you can't plausibly distance yourself from by dismissing them as long-ago mistakes made by a far less mature version of you.)
10. If you are lonely and have no one you can stop being lonely with, it is always much better to go be lonely on a gorgeous mountaintop covered with flowers than to be lonely in your own dark, dingy bedroom. At the very least, if the experience itself isn't enough for you, you can bring a camera to the mountaintop, photograph the flowers, post your photographs on the Internet, and find people who'll want to talk about your trip with you. And then you can tell those people about the feelings that brought you to the mountaintop and the feelings you had while you were there.