Do words and encouragement ever actually change people's lives?

I used to believe in positive reinforcement that if you tell someone that they are beautiful that they'll get motivated and do things to increase their beauty and overall self-esteem. Or if you tell someone that are really smart in a particular field that they'll be motivated and advance in that field which will better their life. And I've thought the opposite where if you tell a really attractive person how ugly you think they look that they'll develop eating disorders and stop keeping up with their appearance. And if you tell someone that they are horrible in a certain field of work that they'll become unmotivated and stop going the work.

I bring this up because I'm quick to say nice things to other people because of this firm belief that I have. But I also have gotten a lot of really good encouragement and information from people on here and yet I'm still in the same rut that I'm constantly complaining about. I've had close members of my family and friends that I feel like they had screwed me over and put me in the position I'm in and they don't even take responsibility for it. In fact they act as if im the one that caused things to happen. And. I've tried to see it in that way and move forward with my life without them, but on three successive instances they've tried to come in my life or they talked to people behind my back. And I don't feel like I should have to start over again because of these people, but I'm also getting nowhere in my life waiting for justice to come out and I can go back to behaving like myself. This kind of took a weird turn and I lost the point I was trying to make.


But yeah do you think encouragement helps people live a better life or are some people just inherently successfully and will succeed no matter what and then there are the opposite of this and these people will struggle in life no matter what.