Elizabeth Loftus (1975) conducted several experiments examining the ability of people to recall events. Her experiments revolved around the common thought during her time that eyewitnesses are a reliable source of information. In her experiments she specifically looked at how the wording of a question influenced the recall of an event. An example of this would be "Did you see the children getting on the school bus?" as opposed to, "Did you see a school bus in the film?" By inserting the word "the" into the question it promotes more affirmative answers.
The reason this happens is that memory is not like playing back a recording like when we play a movie. Memories are made up of events that occur over time and when we recall them they are intermixed with not only the event that we are recalling, but any new information that we have taken in since that event. This causes the memory to be reconstructed based on the new information. By using the word "the" the questioner is giving new information to the person recalling the event and that person reconstructs the event based on the new information, assuming that the questioner is correct about the event e.g. there was a bus even though in actuality there wasn't.
By understanding this we as writers can play upon the retelling of events when our characters are informing the reader. We also must understand that when a character is retelling an event it is not always going to be accurate, but it will have some variance to what actually took place. There will be little parts that one person will see or imagined seeing that another character will not have seen.
Tidbit: I was engaged to my wife two weeks after meeting her and married two months later and yes we are still happily married after 12 years :)