I think a lot of people, probably most people, come to The Power of Now from a place of suffering. They are in pain, and want to feel better, and the power of now seems like a solution.
Ironically, the harder you try to change, the more you realize that you can't. Often times the mind will latch on to these new teachings, and try to become a new version your yourself. The result can be that you start to feel guilty or frustrated at the fact that you still feel sad, still feel angry, and still suffer. You've read the teachings, you have the tools, but they're not working, and in a way, this can feel even worse than the initial suffering.
You can't think yourself free because the solution is not in thought.
You try to clear your mind, but things keep popping up. Again, this goes back to the original trap that I highlighted; you want to change, and have developed an idea of what you want to be, and whenever you fall short of this expectation, you feel frustrated and disappointed.
There are a number of things to consider about the power of now, and the teachings in general;
1) There is a difference between seeing your thoughts, and participating in them. You may hold your hand under a running hot faucet, and when you take your hand away it still burns. But if you do not put your hand in the hot water again, eventually the pain subsides. When a thought pops up, you can observe that it's there, but not engage in it. What is this space that you can observe the thought from? Often times I imagine things that happened in the past, especially instances where people have hurt me. It's so easy to put myself back in that situation and imagine what I could have said, or what I want to say to them. In this case I am participating in this thought and have been whisked away into the past. I continue to suffer by reliving that painful event over and over again through my own willful participation. The other choice is to simply say no. I'm not going to be an actor in this play. I can see the stage, I can see the story, but I don't want to be a part of it. It's still there, it's still happening, but I'm watching from a distance. Can you see this empty space within yourself to observe but not participate? This leads me to the next point;
2) There is no right and wrong. Your mind is going to be full of ideas and beliefs, and they are going to pop up. Don't try to push them away, as they arise, observe them, but do not buy into them and become a participant. I think you will find that it can be briefly painful to have these thoughts pop up, but it is far more painful, and exhausting to actually step into that make believe world, and become an actor in this play of the mind. that's when you really start to tense up and get angry, and that's how you STAY angry for a long time; through participation.
I had a dream last night about someone, and that dream brought some pretty nasty emotional pain that stayed with me after I woke up. On the drive in to work I sat with these feelings and I felt them. I didn't want them to be there, but this was just my reality at that given time. I didn't have to delve into the dream and relive the experience, but instead feel the pain and allow it to happen, but not create a story for it. Sometimes the world is a sad place, and during those times you should feel sad, and allow the sadness to be with you. Over time it will pass on, as all things do.