Some people just know the best thing to say when someone's feeling down and out. They know just how to motivate someone with a few simple words and leave a lasting impact on them afterwards.

Sometimes it can come from a friend or a teacher, or even from the Internet. Everyone wants a happy life, but the road to one can be long and stressful, and we won't always have someone by our side to whisper kind, encouraging words to us, which is why quotes from famous celebrities and speakers can be the moral support we need sometimes.

Here are 21 quotes one should live by if they want a happy and successful life.

1. “Forgive yourself for your faults and your mistakes and move on.” - Les Brown

2. “Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.” - Dr. Seuss

3. "Don't wait for inspiration. Become it." - Unknown.

4. “Tension is who you think you should be. Relaxation is who you are.” - Unknown.

5. "If people aren't laughing at your dreams, your dreams aren't big enough.” - Grayson Marshall

6. "Build a dream and the dream will build you.” - Robert H. Schuller

7. “Don't envy what people have, emulate what they did to have it.” - Tim Fargo

8. “Start where you are. Use what you have. Do what you can.” - Arthur Ashe

9. “Success is something you attract by the person you become.” - Jim Rohn

10. “Develop success from failures. Discouragement and failure are two of the surest stepping stones to success.” - Dale Carnegie

11. “Learn from the mistakes of others. You can’t live long enough to make them all yourself.” - Eleanor Roosevelt

12. “Courage doesn't always roar. Sometimes courage is the quiet voice at the end of the day whispering, 'I will try again tomorrow.'" - Mary Anne Radmacher

13. “What are the most powerful words in the universe? The ones you use to talk to yourself.” - Karen Salmansohn

14. “If you cannot do great things, do small things in a great way.” - Napolean Hill

15. “Everybody comes to a point in their life when they want to quit, but it's what you do at that moment that determines who you are.” - David Goggins

16. “So many of our dreams at first seem impossible. Then they seem improbable. And then, when we summon the will, they soon become inevitable.” - Christopher Reeve

17. “When I let go of what I am, I become what I might be.” - Lao Tzu

18. “Decide whether or not the goal is worth the risks involved. If it is, stop worrying.” - Amelia Earhart

19. “The biggest room in the world is room for improvement.” - Unknown “If you are always trying to be normal you will never know how amazing you can be.” - Maya Angelou

20. “Don't limit your challenges - challenge your limits.” - Unknown

21. “Wherever you go, no matter what the weather, always bring your own sunshine.” - Anthony J. D'Angelo