Unrequited love is when you really like someone a lot, but they don't like you back in the same way. It's like when you want a toy that another kid has, but they don't want to give it to you. It can sometimes make you feel sad or frustrated because you really want to be with that person, but they don't feel the same way about you. It's important to remember that you can't force someone to like you back, and it's okay to move on and find someone who will love and appreciate you just as much as you love and appreciate them.