--WORK IN PROGRESS--
Over the years I have realized that relationships can be classified into the following:
Such relations don’t let you grow. You keep on solving the same problems day over day, and yet remain at the same position.
These relationships push you down, into further depths. They have the potential to hurt your confidence, and self respect.
These types pull you, or take you to newer highs. Its almost the same experience when you hit a thermal. Its exhilarating, but usually short lived - or atleast feels that way.
These help you to vent out your day to day stresses, and keep your cool to face newer challenges every day.
Float (This point came in as a comment)
Someone who just lets you be what you are. No questions asked, no suggestions given, unless asked. Lets you commit mistakes, but does not judge you, or say "I told you so". Is there to support.
EDIT: This is what I would call a 'friend'
One person cannot be slotted into one type. Everyone plays multiple roles.
Who are you, with whom?