What do you wish you'd been told before you left school?

Ask The Readers: What do you wish you'd been told before you left school? - Lifehacker

It's the fair month of May, which means countless graduates will walk across a stage and receive their diploma in the coming weeks. An educator at the Budapest University of Technology and Economics in Hungary writes in:

Some of my students will finish the university this year and leave the dormitory. We've spent 5-6 really fine years together and I'd love to give them some tips before they enter life. What is the thing you wish you'd been told when you just left school?

I could fill a book with things I know now that I wish I knew then, but instead I'm putting the question to you wise lifehackers. Got a life tip to share with graduates everywhere? Share it in the comments - and congratulations, graduates.