PS:
Don’t get locked into becoming an architect. Consider music, especially composition. Take piano lessons.
Learn to deal with Daddy’s abusive anger. Learn how to fight back. Trust me, he will never hit you again.
Don’t get too attached to President Kennedy.
Me,
It’s you here me. From way, way in the future. I’m much older than mum and dad are now so you know what that means?
No fucking worries, you’ll be sweet.
Don’t take any shit,
Me
My life has worked out pretty well, but here are two things I wished I had grasped earlier:
Learn to talk to people. The way to do this is by talking to people. So do things that involve talking to people, like volunteer stuff or gaming clubs
A nice haircut and dressing neatly will really help you with the ladies.
Dear me,
I know you watched The Right Stuff and you just got back from space camp, but listen. You’ll grow over 6’ and never be an astronaut, so don’t get too attached to that particular dream. You’ll do just fine in high school, but in college, you’ll need to get your depression in check and actually do so fucking homework!
Also, don’t get drunk and try triple jumping on wet and slanted pavement. It does not end well and nobody will be impressed. Using crutches to get around campus will make your depression way worse.
If you choose to share your bed with someone else, choose your side wisely. You will never - ever - get another chance. It doesn’t matter if you change houses or stay in a motel. It won’t matter if she’s away on a business trip. You will sleep on your side… or she will know & it will have been the wrong choice.
Most cats are better than most people. Prioritize appropriately.
Calling the police is better than taking matters into your own hands.
10-year-old me? Yikes. I was pretty clueless in 5th grade…
Hey, there. Those jerks who are being mean to you? Tell your parents.
Ride your bike more, you need the exercise. Tell your parents you don’t want to end up diabetic like Grandpa and make them buy you some running shoes and RUN.
I know school is hell of easy for you, but push yourself to learn everything you can. Especially Spanish & French; in the long run, being able to speak a foreign language will be more important than you realize. Forget about music and study electronics instead.
When you get to high school, go to the Sandpiper and get a job as a box boy. Earn some money, save some of it, and ask Laurie out.
Move away from this town and the family at the very first opportunity.
Your gut ain’t wrong!
Dear Me,
Your parents are completely untrustworthy. Don’t trust a word they say. You’re on your own.
You’re going to get really ugly and there’s nothing you can do about it. Make your love life a priority sooner than later.
Pursue S, not P. Trust me on this one.
Don’t work so hard; it isn’t worth it.
In the seventh grade, some girls at your table in Home Ec will bully you.
For God’s sake…ask the teacher to move you to another table!
Here’s a roll of 1965 D quarters. Don’t bother saving them; they’ll be worth the same in 2019, but with less buying power. Use them to buy clues about every girl you are attracted to. Hints: L yes, L her roommate yes, but you may not find out until you’re already married. K yes, but that’s obvious. She’s also bi, which could be cool but you won’t be sure until after you’re married. Maybe hold off on marriage. You’ll have twenty good years with P, then twenty lousy years, then she’ll die. C probably, based on what she said at your 20th reunion. Don’t push it, but DO SOMETHING. E probably; ask her to a movie, FFS.
I could go on, but I’ve said enough. Oh, they don’t mind that you’re a bit chunky, so quit being self conscious. And don’t say anything stupid.
For those who prefer terseness, we had this similar thread two years ago, in which the messages were limited to 140 characters.
ETA: Baker, you wrote similar things back then!
Dear Mini-Guest-starring: Id!
Screw your Creative Writing B.F.A. and commence your illustrious gardening career, like, a couple decades earlier.
Dear 15-year-old R: Please try not to be so smug and judgmental. And the one eternal truth is that you can never teach anyone anything.
Dear beck- You’ll still be alive in 2019. Make adjustments now. Don’t burn your bridges too quick. And Stanley is a creep, btw.
Steal your older brothers Beatle albums when he leaves for bootcamp. Leave the Haggard and Jones. Have fun at college.
Dear Tae -
In a couple of years, you are going to get a part-time job. Get in the habit of taking 10% of every check and putting it in a savings account. Do this for every single job you ever have.
Also, you’re going to start bowling when you are 12 and learn to play guitar when you are 15. Practice both of them diligently - there’s money to be made with both. Don’t forget the 10%.
And exercise more. When you graduate high school, you will be in the best shape of your life. Keep that shape. Don’t sit on your ass.
Leave Jay and Bruce alone. Being mean to them isn’t funny, it won’t make the other kids like you better, and you will regret it for most of the rest of your life.
There’s probably other stuff I could say, but most of it wouldn’t be understandable to a ten-year-old and / or is trivial in the long run.
Dear Hari:
Don’t take up smoking. If you do, you will have a heart attack when you are 28. Elaine is bad news but good experience. Same with Louise. But when Marcia comes along, don’t hesitate.
Other than the smoking (and maybe lose some weight), just carry on.
Put a little effort into school, rather than just coasting and always doing the bare minimum.
Study the math and science - you can, it just takes a bit of effort, and it will open up what you eventually will really find interesting.
While you are at it, pick up a second language.
Don’t be a lawyer just because it is easy for you. You’ll make decent money, but will not enjoy any aspect of your career.
DO NOT stop music lessons when your parents give you the option after grade school. In your 50s you would kill to be able to play piano like you did at 12.
Date more in high school.
Don’t hang as much with the partiers and stoners.
Try to enjoy the time your dad requires that you spend with him doing home repair stuff. There’s going to be a time that he is gone, and you’ll miss being able to spend more time w/ him. Plus, that guy could fix ANYTHING.
When you find yourself in the woods with a kid named Fred, and he fakes having a sore ankle, grab the opportunity, like he wants you to. He’ll be your first. 
To 21-25 year old “me” circa early-mid 80s;
Cut your hair a couple inches shorter, and lose the mustache, and lose the torn jeans and mid-riff cut T-shirt. While you’re bright, have a great work ethic and you’ve got a good head on your shoulders, you may never get a chance to display these qualities to good effect because you may ( and probably ) will be judged in lower regard in both the workplace and dating scene because you look like Tony Iommi.
Note: Absolutely no reproach to Black Sabbath and Tony Iommi as such.