You are who you choose to be. That can be a difficult pill to swallow. It means that you are responsible for yourself and everything that you do. All the good parts about you, and all the bad, are of your own choosing, though you may not be specifically aware of the choice (or choices) that led to specific traits.
It is also difficult because it is difficult to accept the power that gives you. If you have the power to control who you are, then anything you can no longer blame anyone else, including your parents, for whatever traits you don’t like about yourself. If you can control how you react to any given situation, then any time in the past that you have responded poorly, it was 100% your fault. That’s a very unpleasant concept, and makes it difficult to accept the power of conscious choice. If you don’t accept it, then you can continue to deny the blame… though that doesn’t mean it belongs any less to you, you can at least deny it, even to yourself.
You’re making the choice of who you want to be already, whether you know it or not. Your conscious mind makes the choices, but it can lie to itself, though not to your subconscious. You can tell yourself that you want to be this way or that way, but not really mean it, down at the level where thoughts turn into concrete decisions and actions. You may say you want to be generous, for example, but below that, you may have a fear of scarcity that keeps you from acting out what you say you want.
When you accept the conscious power of choice, you take the power from these lower layers, where such fears dwell, and bring it up into your awareness. Now you can take those things that you say you want to be and consciously examine them to determine if that really is who you want to be, rather than something you think you should be because others tell you so. If it’s truly who you want to be, then you can take it from just words, and turn it into a decision, and embed that decision in the bedrock of who you are.
How long it takes to do that depends on how truly you have let go of the concept of powerlessness. When you have truly let it go, and completely understand and accept that you are who you choose to be, change, even drastic change, can be nearly instant (referring to a change in who you are, not what you are… changes to your physical body will still take time, though quite possibly considerably less, since you will not be conflicted and fighting yourself). If you are just beginning, it may take several times making the decision to add or remove a trait to really embed it deeply.
Once you accept this power, it also leads you to the knowledge and acceptance that all of your emotions come from inside you, too. You choose which emotions to feel, and how strongly, though often your choice may not be “I’m going to be extraordinarily happy right now”, but something more like “Those circumstances will no longer bring anger or pain”. That’s not to say that you can’t make decisions about how to feel and make them instant, but it takes more work, more energy, and therefore is not as common.
After you’ve accepted the power of conscious choice, and experienced it for a while, you are almost certain to be more at peace. In fact, it’s hard to NOT have that as your default state. After all, if who you are, what you do, how you feel and react, if everything about you is your choice, what is there to be conflicted about? You may lose your peace from time to time, when you slip and give up your conscious choice, letting your subconscious back into control, but as soon as you return to conscious awareness of choice, your peace will return.
Incidentally, when you have this state of conscious awareness of choice as your normal state, other people will notice. People may turn to you for leadership, since they can see that you have it together. They may come to you with questions and problems, some of which you may wonder why they thought you could help. They are likely to give you trust, often trust far beyond what they should give someone they know to the extent they know you… you may find strangers telling you things they would be better off keeping to themselves. Most of all, they will see you as someone they should emulate, which can bring positive or negative responses.
Acceptance of that awareness, the power of conscious choice, is good for you and good for others. It can bring peace and harmony to you, as well as improving your ability to make choose the path that is best for you in any number of circumstances (the best for you in the sense that it fits who you are the best, not in the sense that it brings the most gain to you in the eyes of the outside world). It shows other people that “people” can learn to respond to situations in the way they choose, rather than just letting their subconscious respond. It shows them that ongoing, lasting peace is attainable by someone they know, not just some Tibetan monk chanting in a Buddhist temple. It might even lead them to the knowledge that they, too, are who they choose to be.
Update: On a personal note, I went through this process of realization and becoming aware the first time around ten years ago. At the time, I had been suffering from severe clinical depression for years, though I had never been treated for it. My depression caused me to sleep very little, until I was down to about 45 minutes per night, which causes all sorts of interesting experiences after a few days (or weeks). It got to the point where I was hospitalized, and for the first time given medication to help (I think the medicine they gave me to let me sleep helped nearly as much as the anti-depressants). I was given a month’s worth of Prozac, and that really helped… it pushed back the funk far enough that I could actually think clearly. It was at this point that I began (I still have slips) to acknowledge control of my own thoughts, feelings, and actions. Since then, I have had one major backslide into depression (which was around seven years ago), where I needed medicine to help. Again, I only needed one month’s worth of aid from the pills, and I got my mind straightened back out. Since then I have had a few slips, including one just the other day, but now they only last hours. I have taken ownership enough that it has changed my subconscious mind’s natural reaction to bad things, where instead of dwelling on them, I consider them and let them go. I can’t even begin to accurately describe how much of a difference that makes… it’s an absolutely amazing change.