When realizing this it can sometimes put a big damper on people you believed were true friends. The truth is. You will most likely only find few true people that will be there for you through think and thin. But don't let this get you down in life. Never stop being the great person you are because of how other people act.
What I do suggest is taking all of these life learning lessons and have them to help you grow into a better person than you already are. I won't lie. I have dealt with plenty of good people and plenty of shady people. At this point of time there is really no avoiding it unfortunately. But there is something you can do about it. Let me give you a example of one of my personal experiences to give you an idea.
I dated this girl that I thought for sure I would be growing old with. We built a house together. We had a ton more great memories than any of the bad ones. I thought for sure she would be who I would take my last breath with. Then out of no where. Well at least I was blind to the fact until after the matter. But out of no where she asked me to leave a house that we spent six years building together. To be honest at first I did the worst thing I could have and begged her to keep our relationship together. Well anyone that can relate knows that that just pushed her further away and made things worse. But after quickly realizing that there was nothing I could do to change her mind. I accepted what was happening and started to slowly plan for me moving out. It was definitely one of the hardest things I had to do in life given we had invested so much time together in building our home and relationship. And when it comes to grieving there is no time limit.
But the point of the above paragraph. Is to show you that no matter how much you think you know someone. Or no matter how much you think things are going right. Life can throw in some wicked twist to try and throw your maturing and growing out of whack. The fact is. The only person you will ever truly know is yourself.
So when life is twisting and you might think at the time it will be impossible to beat. Just remember reading this and knowing that you can overcome anything with the right mindset. It may not be easy. But you will be able to overcome anything life throws at you. Like I said before you will find the few people in life that will be there through think and thin, and when you do keep them close to your heart and treat them right. But there are many people that will come and go. Just know that it is okay and never stop growing and learning as time goes by. No matter who is in your life and who is not.