Why do we remember things?

As part of my daughter's nighttime routine, I have to tell her 3 stories.  It used to be that they were any stories, so every night I would tell her fairy tales (removing the death, which surfaces surprisingly often in conventional children's stories) or make up stories to tell her, or a combination of both.  Once we'd gone through the standard stories, I was making them all up, which is rather difficult.  I take pride in the fact that I could always think of 3 stories.  

Then one night, I made up a silly story about a little birdie named Hobo and his little brother named Rex (if I'd known the Hobo and Rex stories would catch on, I would have made their names better).  My 3-year-old daughter latched onto Hobo and Rex that night, and the nightly routine transformed into my having to tell her 3 stories about Hobo and Rex, not just 3 stories in general.  So for the past 6 months or so, I've been coming up with 3 Hobo and Rex stories every night.  I wish I'd written them down.  I'd have a novel at this point.  I have been incredibly bored with Hobo and Rex the past few months, and foresaw years of having to make up stupid stories about those 2 birds.

Tonight, as my kids were getting dressed for bed, I mentioned to my daughter that I used to suck my thumb as a child.  Hooray!  A new bedtime story genre has entered her mind.  Tonight, I started to tell her 3 stories about Hobo and Rex, and she stopped me and said, "No, Mama.  Tell me 3 stories about you!"  I was delighted to get to do something different.

Which brings me to the point of this post - what makes us remember what we do?  The first 3 stories about myself when I was little that came to mind were:

1) The time I had the chicken pox and there was a ton of snow on the ground.  We lived in the DC Metro area and lots of snow was rare.  I wanted to go out and play in the snow so badly but I was sick.  I remember looking out the window of the side door and being crushed that I couldn't play in the snow.  I was probably 6 or so at the time, and the snow probably wasn't that deep, but it seemed like it to a kid.  My mom finally relented and I got to go play outside for just a few minutes.  I think I also remember my dad laughing at a neighbor's pet (cat? dog?) making tunnels in the snow because it was so deep.

2) The time we had to hunt for Easter eggs in the house because it was cold/raining and we lost one.  My mom didn't hard boil them because she didn't want to have to eat 3 dozen hard boiled eggs, so they were just raw.  We managed to find all of the eggs but one.  I recall that one egg being missing for weeks, and my dad finally found it because of the smell.  Again, I think I was 5 or 6?  I think it was in our old house (we moved when I was 7).

3) The time I walked over to my friend Karen's house (again, when we lived in the old neighborhood) and we made kid-sized "bird's nests" from all of the leaves in her backyard.  I remember it was fall (obviously) and cold, and I remember sitting on the cold ground in the middle of my "nest."  I don't remember whether or not I thought it was fun, just that we did it.

How random are those?  I can see where the chicken pox memory might stick, but why the bird's nests with Karen?  I probably played at Karen's house thousands of times, but I couldn't tell you one other thing that we did, or even tell you what her house looked like.  I think it might have been green?  I remember that the wires from the power lines went right into the side of her house, which was weird to me as a kid.  I believe at our house the lines went into the ground then into the house, but I digress.  I think about the things that I remember from being a kid and I have to wonder why those memories stick, but other ones that you'd think would be more substantial, completely fade.  Just curious, I guess.

Off the subject, my husband is watching movie previews because we're trying to pick a flick to watch tonight, and I just have to add, in closing, that Ed Harris is the mac-daddy.  He kicks ass in every movie I've seen him in.  Thank you.