Let me give a counter to what Osteen seems to be teaching.
Chesterton begins the second chapter of his book 'Orthodoxy' with the recounting of a conversation he had with a friend, in which the friend commented about some that he will do well, because "he believes in himself". Chesterton tells his friend that if he wishes to see the people who truly believe in themselves, he could tell him where they could be found--in the mental hospital. When the friend disagreed, Chester pointed out that yes there were those not in those institutes who did believe in themselves--they are the people who try to succeed at things they really have no business doing, and no one can tell them otherwise. "It would be much truer to say that man will certainly fail, because he believes in himself".
I returned to tournament chess last summer, at a small unofficial tournament at a library. I did not go into it with much confidence--my last tournament had been a blitz chess one in Perm, and I had had no success worth mentioning in it. I could console myself on 'holding my own' in a few games, but that was it. My expectation were not high, but I was determined to do the best I could in each game.
At the end of that tournament, I had 5 1/2 points out of 6 games, and was first overall. I've since learned that the competition wasn't of the highest, but I was and still am happy with that result.
Why do I mention this? Because, to put it simplest, I did not go into that tournament with some kind of 'believe in myself' pep talk running around in my head that I told myself over and over. If anything, I was nervous and on edge, taking nothing for granted. I played some good chess that day, made some good combinations, but I was 'playing scared', trying to make as certain as I could of every idea I tried.
But let's do an experiment. Let's say that instead of playing against players who were not very strong, I was playing against real Masters and Grandmasters. I could name, say, Kasparov, Kramnik, Shirov, Greev, Anand, and probably others who are among the world's best, so let's say that for whatever reason, they were in Lexington and decided to drop in on the lowly little library tournament to compete.
Do I win that tournament with them in it? Not even in a fantasy world as far out a Pratchett's Discworld. In the six games I play against them, in at least half I will be either lost or in a losing game in under 20 moves, and would be quite pleased if I could make an interesting game in at least two of them, and would be tickled to death if one actually ended in a draw.
Towards the end of my time in high school, and for about a year after that, I seriously believed I could make it as a golfer. I played several times that summer, hit the practice tees, putted and chipped on the practice greens.
Not without some success. I started the summer shooting in the 150s, and a few times made it down to around 100. For those not in the know, that's not even close to a professional score. And the course I played on wasn't as difficult as even the easiest of tour courses.
The thing is, I believed I could. I could see myself wearing a Master's green jacket, of going up against the top players of that time--Greg Norman, Curtis Strange, Nick Faldo--and winning (and considering Norman's fabled bad luck, it maybe wasn't that far out of a dream).
And I was wrong. Reasons for why I failed could perhaps be found on analysis (a really bad swing was perhaps a big reason), but not all of the positive thinking and self-belief in the world could have made more then 5 strokes of difference, and I needed about 30 there at the end.
And, really, I don't regret that failure. To quote a particularly moving country song, "There's no way to know what might have been", so if I had succeeded, my life would no doubt be much different then it has been, whether better or worse may be something else. The thing is, I like how my life has been--not easy, and I doubt I've made every decision correctly, and certainly there have been crazy and even painful times. Nor am I necessarily completely satisfied with my lot right now, but that may be problems in myself.
But it's been a good life, too, and I've done a few things that I don't regret. I've met people I can admire and respect, I've made good friends from all over the world, and I've found a type of work that I have skills at and that I enjoy doing.
So, I'll take my golfing failure, thank you very much, and no amount of nice-sounding words on Osteen's part will rob me of that. And if it seems negative of me, so be it, I've rarely felt the need to live up to some kind of 'positive only' mindset. Reality is quite often negative, and even God does not blind Himself from reality.