Sitting down and wondering what went wrong? It is a great thing to introspect and it is even better if you can come up with something that is conclusive. For instance, I have been introspecting and realized that you don't need people in your life. You need just a focus...a focus on your targets and in this process you will come across humans. But there is no need or compulsion that you have to be good to them or something of that sort. This also doesn't mean that be bad to people...but just don't attach yourself. There is no point of attaching yourself to these variables. Tons of people will come and go, what you need to do is to get the best out of them and move ahead. If you master this art there is no stopping you. Look at the greats of any era, they did not have any time for people. All they did was that they focused themselves on something good and everything else became secondary.
"If you want to go fast, walk alone.
If you want to go far, walk together."
We all are here in the pursuit of happiness and you need people in your life to be happy because happiness is real only when shared. Watch this movie called "Into the wild" for that.