Comment From Merriam-Webster (Score 1) 102
from http://www.merriam-webster.com/dictionary/mania
Definition of MANIA
1
: excitement manifested by mental and physical hyperactivity, disorganization of behavior, and elevation of mood; specifically : the manic phase of bipolar disorder
2
a : excessive or unreasonable enthusiasm —often used in combination
b : the object of such enthusiasm
So, in conclusion: it's the object of excessive or unreasonable enthusiasm, not the best thing since sliced bread.