Everyone learns the basic life lessons. Not everyone heeds them, but they learn them nonetheless.
Each family has their own individual random lessons that they bestow upon their children; who at the time, are probably too young to understand the value of their elders' words.
Here's what I got:
1. If you donate a computer, keep the hard drive. That little brick of scrap metal holds all your personal information. 98% of the population are good, honest people who wouldn't think or bother to steal your personal info. Do you really want to risk donating your stuff to the 2% that have no problem stealing your information?
2. If you have to walk to your car at night, walk with your keys between your knuckles. I worked in a grocery store that was on the edge of a slightly sketchy neighborhood. It was typically safe, but usually creepy. I felt a little better and more powerful when I was walking to my car alone at 10pm, if I had my keys in hand and ready should someone come at me.
In the same family, peek into the backseat of your car before you enter.
Also, lock the doors as soon as you get into your car. Don't bother checking your texts, just focus on locking the doors and getting on your way.
3. If your mom tells you you look ridiculous, then you probably do. Sixth grade fad: slicked back hair with scrunchies layered. I maxed out at 7 scrunchies. I looked terrible. My mom told me "someday you're going to look back at [school picture] and be angry that I let you out of the house looking like this." She was 98% right.
4. If you ignore them, they will eventually stop. This is not true 100% of the time. Sometimes you encounter someone relentless or someone who isn't feeding off your reaction; however, those situations are rare. While ignoring may not be the best solution past the age of 21 and after university, you can still apply the "ignore" rule past graduation. Boss sending you harassing emails about the report that's due next week? Say "I'm on it, and I'll have it to you as soon as I'm done." Sending a response, and there is nothing there to fuel any kind of weird angry fire they may be burning at that time. This brings me to my next point of...
5. Record everything. This is for your protection. If you have a questionable interaction with someone, record it. Write it down as soon as it's over so everything is fresh. If someone sends you a crazy/inappropriate text, screen shot it. If your boss sends you an questionable email, screen shot it. It has really saved my ass in the past, because I was able to prove that someone at work had indeed said inappropriate things (they were denying it, and I could have gotten in trouble if I was unable to prove that they had been harassing me).
6. It is better to beg for forgiveness than ask for permission. Sometimes, the offense isn't actually as big of a deal as we build it up to be. Obviously, this only holds true for the smaller things.