Get ready for some feels as we introduce Mantis. One of Marvel's greatest empaths as the ability to feel others emotions and alter them completely. As you can imagine this can be used to do harm, which is exactly what her father Ego - who is also Starlord's father - would use her for. Having been raised in isolation and used as a tool by Ego, Mantis had very little knowledge of actual social interactions and was naïve on how friendships should work, or even what they are.
At some point in her story Mantis escapes her isolation with Ego and joins the Guardians of the Galaxy where she bonds with Drax and the others and we can see her grow emotionally.