One who possess much thuse.
They are both plumbing enthusiasts.
A person who does something for a very long time but still sucks at it though he enjoys it very much. Thus, the term enthusiast is given to him as a consolation. A pejorative synonym of the term is "sucker". However, the pejorative synonym is not used commonly because an "enthusiast" may suffer lengthy bouts of depression and suicidal tendency since such pejorative labeling would make him reflect on his sad life. A urban legend states that if a person calls an enthusiast a sucker the enthusiast may turn to a gremlin at midnight devouring the person's soul.
He is a piano enthusiast. He has been playing for fifty years but can only play "twinkle, twinkle little star" albeit the numerous mistakes
Enthusiasts are unfortunate people.
If you do not want to be an enthusiast it is best to work smart not hard.