John, Paul, George, and Ringo. You're bound to be from another planet if you don't know them. After 40 years, the Beatles are back with digitally remastered versions of their albums and they sound better than ever.

The lyrics of their songs are simple and catchy, making them easy to remember. Furthermore, their music tackles themes we can all relate to, such as love, anger, nostalgia, social issues, to just plain fun, made to fit every mood.

Here are 10 Beatles songs you definitely should have in your play list.

1. "Here Comes the Sun"
When to play this song:
This song is guaranteed to sprinkle a bit of sunshine into any drab day.

2. "In My Life
When to play this song:
It provides great accompaniment when blogging or writing in your journal. It's also commonly heard in debuts, weddings, birthdays, and other special occasions. The slow, moving song triggers nostalgia and brings about sweet memories of happy experiences.

3. "I Will"
When to play this song:
Play this song before sleeping; its soothing melody is sure to relax you and make you forget all your worries from the day.

4. "Yesterday"
When to play this song:
Heartbroken? This is the perfect complement to your melancholy. This song was such a hit, that it made it to the Guinness Book of Records as having the most cover versions ever written!

5."Twist and Shout"
When to play this song:
Play this song in the morning. Its fun and rhythmic beat can liven up your mood and remind you of the parties in the 1960s when people danced to this tune, twisting and turning in party dresses and suits.

6."All You Need is Love"
When to play this song:
It has one of the shortest lyrics among all the songs of the Beatles, yet it remains meaningful. With its cheerful melody and the trumpets playing the background, it does the job of a much needed pep talk when trials come your way.

7. "Hey Jude"
When to play this song:
This song will make up for a very lively videoke experience. The song reminds us to not take life too seriously. "Take a sad song, and make it better!"

8. "Help!"
When to play this song:
Listen to this song on a road trip with your friends and family. It’s so easy to sing along as the melody doesn’t require vocal gymnastics on the part of the singer.

9. "A Day in the Life"
When to play this song:
Listen to it at night, or when you're in chill-out mode. The melody and the lyrics of the song have this almost out-of-this-world eeriness to it that makes anyone want to listen to it one more time.

10. "Act Naturally"
When to play this song:
Play this song before a tough interview, a presentation, or anything you’re nervous about. Don’t fret; all you have do is act naturally!