If you're wondering about this you have probably had friends or family tell you whatever horrible experience you had is why you're acting a certain way. It's usually those we love who get the brunt of it in the form an over reaction. Or you may be the kind of person who keeps things in and does a lot of pretending. Especially if those bad experiences involve family members you may still have to interact with. We feel like we have to keep this past experience where it we want it to stay, in the past. It may feel like something so far removed from your life you don't see how it could possibly be affecting you today. It happened years ago, maybe even when you were a kid, so how could it be affecting you today? You may not even think much about it and in fact do everything you can to not think about it.
If this experience was something traumatic, something where it felt like there was a definite before and after, it is probably affecting you in some way. I say this for two reasons. First of all we are all products of our past experiences, good, bad and in between. This doesn't have to be a negative thing. We all have heard of someone who overcame a negative experience and it shaped their life in a positive way. Think Tony Robbins, Oprah Winfrey, Maya Angelou and the list goes on. We cannot escape the fact that things that happened to us shape how we see the world, the kind of spouse we are, the kind of parent we are, the kind of friend we are. It is simply a matter of degree. Is our reaction mostly about what is happening now and a little about past experiences or visa versa? The clearer we are on that the more in control we become of the past not getting in the way of today. The second reason I believe this may be true is because of what happens to us, to our brains when we go through something traumatic. That memory is stored differently than a regular memory. This is a protective mechanism. Think cave man days when we lived in the jungle and saw a lion under a tree. The next time you walk by that tree your heart will beat faster, adrenaline will be released just in case you have to run and you will be hyper-vigilant waiting for that lion. That is exactly what happens when we are triggered or reminded of a past traumatic event. This is a physiological response not a thought you have. You may not know why you are having the reaction, especially if it is to something that happened in childhood. But it will cause you to avoid things, react stronger that is normal in a given situation and most certainly affect your life now. If this traumatic event is something recent it will be easier to put together why you're having the reaction.
Most people see no connection between a childhood trauma and reactions they are having today. Many times it is only after these reactions have affected your life in a serious way that you begin to wonder about this. They are connections that are difficult to see because they are so automatic and have been there for most of your life. The more conscious you become of these reactions the more control you gain over them and over your life.