If I could give one piece of advice to the old me, it would be that people are going to hurt you but don't make that a reason to be as low as them.
You're going to get let down throughout your life; especially by people you wouldn't expect it from. Most people find this as an excuse to why they are now so emotionless and cold-hearted, but just because you have been hurt by someone does not mean that you should drop down to that level.
Now, I'm not saying that this means you should let people walk all over you, definitely do not let this happen. Let people know that what they did hurt you but instead of being upset and angry over this, be a good person. No matter what negative things life throws at you, always be a good person because no one is going to look back on you and have anything poor to say about you if you're more valued than that.
People have told me on multiple occasions that they are surprised that I put up with the amount of crap I do and I let people get away with. But the thing is I'm not letting anyone get away with anything and I'm also not putting up with anything. I've accepted the fact that not everyone is going to be as generous as me and some make it their goal to tear others down. There is no point in letting this effect me to the extent that I remain angry about it and hold a grudge. Instead, I let others know they have let me down and I move on past it. I did nothing wrong and I have no guilt to live with, they on the other hand do.
So always be kind to others, regardless of what they have done to you. In the end you'll be able to sleep at night much better than they can and you'll also live a much happier life.
