Happy D. Monkey is the younger brother of Angry D. Monkey. When you look at them you can see the resemblance; but personality wise they are very different. While Angry takes a pessimistic look at everything, Happy is more optimistic. This is mostly because of his young age and his naive outlook on everything in the world.

Happy is also one of the few people in this world who can get Angry to actually smile. It's quite a skill, considering who Angry is.

• Happy as with what seems to be a lot of main characters was not originally going to be in the series. He was one of the latest additions. I decided to add him about 2 pages before he appeared.
• I don't know if anyone has noticed but Happy's hair thing has seemed to get longer as the series has gone on. I am always tempted to just give him a haircut or change his hairstyle.