Forgetfulness can be improved in many people. It requires work.
Many people suffer from some level of ADD (attention deficit disorder) and those people will have more problems remembering simply because they didn't pay attention in the first place.
I expect practicing yoga and meditation might help ADD sufferers but, if they're like me and lazy... I'm about as lazy as it gets, then shorter faster solutions are in order.
The best memory jolter is trying to remember by association. You have to consciously tell yourself you want to remember whatever at the time you are exposed to it and think up something as a reminder tool... this takes practice.
Recalling events is hard to do unless you were affected emotionally by the event. But, like the memory jogging technique, it requires a conscious decision to want to remember and you have to look for some kind of memory jogger to help you out. For instance the person may be wearing a red dress, or a pink tie, or something. Try to impress that little detail in your mind at the time. Then when you next try to remember the person that little detail may come to mind. Then the rest will start flowing.
So... the short answer is some people are just plain forgetful and others have a natural ability to remember. Likely because they paid more attention to detail at the time.
Guess that sucked didn't it. Now all you have to remember is it sucked and you'll remember me.