Acceptance seemingly has two sides - acceptance of others, and acceptance of oneself. However, if you examine it more closely, they really stem from the same place. You could probably find 20 distinctly different definitions for the term acceptance, and they could very well all make sense. To me, however, acceptance is acknowledging yourself, another, or a situation, exactly as is, and understanding that "it is what it is". It doesn't mean you have to love it. I might gain 10 pounds and not be overjoyed by it, but I acknowledge it and understand it instead of feigning ignorance or refusing to realize that it's true. It is the same with a relationship break up. Instead of making up numerous scenarios in which it might not really be over, or citing reasons for the breakup that are obviously inaccurate but make me feel better, I need to say "ok it's over. That's that." Perhaps it's not over permanently, but it is at the moment. And once I accept it, I can start to move on. But not until then.
Acceptance is one of the most difficult concepts for me to grasp, I'll admit. But I need to separate acceptance about something from being happy about it. They aren't the same. One is acknowledging the truth and saying "I have to go from here". The other is feeling delighted at that truth, and there are some circumstances, many in fact, that just don't warrant delight at all.
Here's a surprising "secret" about acceptance, though: when you accept a situation you've been avoiding, when you've acknowledged the whole truth and nothing but the truth, it's actually a relief. It can release, in fact, a whole range of emotions - sadness, frustration, anger, hurt - but it also brings relief. It's like when you know a secret about someone or you've told a lie for someone, in this case yourself, and you've held it for so long, and you finally get to bring forth the truth. Even if the truth isn't something positive, it feels good to release it none the less. You're no longer responsible for covering it up, for playing that game. You don't have to constantly wonder when someone will find you out, because you now have nothing to hide. It's the same with acceptance. When you finally are 100 percent truthful with yourself, it feels almost refreshing. You can start anew with whatever that situation is. And it's the same with accepting others - you don't have to hope or pretend they're anything they aren't, for better or worse. You can take them at face value, and determine your interactions with them from there.
What facts or situations do you need to accept about yourself? About others in your life?