Your life is not as you remember it. Neither is mine.
It's bold claim to make, I agree. So let me elaborate:
Think about your next vacation. How much money are you willing to spend on it? Now, how much would you be willing to spend if, at the end of the vacation, all pictures were deleted, all souvenirs taken, and even all memories erased? In other words, how much would you spend if you knew that you would not remember anything about the vacation?
Think about it.
I'd wager you would spend a lot less money in the no-memory case... maybe nothing at all!
But why? If we still get to enjoy the vacation, why should it make a difference if we remember it? Therein lies the rub!
Experiments have shown that we essentially have two selves: the experiencing self and the remembering self. The former lives in the moment and the latter looks back and evaluates. But the most interesting part is that the two usually disagree!
But how could they disagree? I mean, we are the same person in both instances. The trick lies in how we remember.
It turns out we don't store every moment in our memory. Instead, we store prototypes of events. For example, think about your commute to work. You likely don't remember every moment of every days' commute. What you do remember is a prototypical, average commute. If something was different today ("oh look, a Starbucks is opening") it stands out because it is different from the prototype. So now your mind stores the prototype and the new exceptional case. So the memory of all of our commutes is essentially a file of a prototype plus exceptional cases.
Let's take it a step further. There are many moments in a commute. How does our mind determine what should make up the prototype? If it picks the wrong moments to represent the entire event, we will have a discrepancy between the experiencing self and the remembering self. As it turns out, this is exactly what happens.
One great experiment involved asking subjects to put their hands in bowls of cold water. At frequent intervals, the conductor of the experiment would ask them to rate the discomfort they felt in their hands (the 'experienced' rating). At the end, after they removed their hands, they were asked to rate how negative the overall experience was (the 'remembered' rating). I ruined the surprise already, but: the two types of ratings almost always disagreed!
If you look at the results of this experiment, you will find that the 'remembered' rating is about equal to the average of the peak 'experienced' rating and the last 'experienced' rating. All other 'experienced' ratings are ignored. Interestingly, the total time of the negative event is also ignored.
From a purely mathematical standpoint, one would expect that the overall 'remembered' rating should be the integral (the area under the curve) of all of the 'experienced' ratings. But our remembering self uses the above peak-end calculation instead.
So, the way we remember our lives is not the way we have actually experienced them.
For a much more detail explanation, please do read Thinking, Fast and Slow by Daniel Kahneman.