Know your limits, but never stop trying to exceed them.
Life is like a 1,000 page book. You want to quit halfway through, but then you realise you have a lot left to look forward to.
If you seek to understand the whole universe you will understand nothing at all but seek to understand yourself and you will understand the whole universe.
Life is a maths equation. In order to gain the most, you have to know how to convert negatives into positives.
If you want to be incrementally better: Be competitive. If you want to be exponentially better: Be cooperative.