Class created for the sole purpose

 Priests were referred to as the one class that was created for the sole purpose of healing and reigned supreme over them all back in the early days. They are armed with more healing spells than the other classes and have a palette that includes HoT spells, AoEs and a variety of direct healing spells. They also have the ability to control aggro and can buff other team members.
As a Holy Priest, the first healing class we ever played which we leveled to 70. We planed to start anew with a restoration Shaman and have not been able to make more Runescape gp ever since after being constantly killed within seconds of being targeted in PvP. There are two main reasons like rapid mana depletion and low survivability, which contribute to this lack of desire. Also, Priests only method of recouping mana is a spell that has to be channeled. When going OOM in the middle of a boss fight, this is very difficult to do.