When you was a child around 9-10 years old and was allowed to go about the neighborhood with your friends or family and out of nowhere BAM a dog starts chasing you. You take off running and jumped on a car or over a fence. Your body produced the chemical Noradrenalin which increased your energy to out run that dog at a speed you didn't know you had. At the same time shots of adrenalin was released also. Once it's all over and you're at home talking about it you start to feel the excitement that you got from out running the dog and you may say "let's do that again" or you may even just go that same way hoping the dog comes out chasing you again. No, you are not crazy, you just like the feeling of excitement that you felt while out running that dog.