Why are friends so important? They determine how you feel, they’re contagious. Now, it’s not just colds and such, but moods and feelings. Have you ever had a day, where it’s just going great and then you talk or see someone who’s having a bad day, and they’re just super depressed or strange and you try to help them up, but in the end, you end up having a hard day and become depressed. On the other had, sometimes you can be having a hard day, and then someone makes you feel happy and then you end up having a great day. It’s pretty amazing isn’t it?!? So, not getting too scientific, what causes this dramatic change in people? It’s mental. As always, if you see or do something that gives you a good rush of emotion, you feel good or excited (a.k.a. adrenaline). But if you see or do something that scares you, or stresses you, well, it makes you feel sad (a.k.a. Norepinephrine). The brain receives these messages, and due to the sensitivity and empathy levels, it receives the messages differently. So, the way people act has a huge effect on you, and how you feel and act, so it is very important to choose good friends.