If you don't make mistakes, you're doing it wrong. If you don't correct those mistakes, you're doing it really wrong.
Putting off an easy thing makes it hard. Putting off a hard thing makes it impossible.
A conclusion is the place where you got tired of thinking or you needed to hand in your test paper.
Education is what remains after one has forgotten everything he learned in school.
Life without problems is like school without classes; you're probably not going to learn anything.
If you're walking in a group of three and suddenly the pavement isn't wide enough for all of you, always walk in front and lead the pack.