Most important thing I ever learned

What is the most important lesson I have ever learned? I don't know, I've lived for 18 years, I've learned a lot of lessons! Look both ways before crossing the street? I got it! Procrastinating. Don't procrastinate. I learned that the hard way. All through high school I put off all the work I had to do until the very last possible moments. Too many times I put off assignments until the morning they were due. It caused so much undue stress in my life and none of my work was as good as it could have been. Also, it wasn't enjoyable to wake up at 4 am to write a paper I had weeks to do.