Devotion

I consider the word "devotion" rather puzzling. It can have several meanings. One is faithfulness to a cause, another is worship of a deity, or dedication to someone's well-being. But some people who have devotion often fall into the trap of identifying it with fanaticism. They end up blinded by the rules, obligations and prohibitions imposed upon them, believing that following the prescriptions to the letter is enough to make them "perfect". In so doing, they stop leading a healthy, normal life. At times, blind faith in an ideal (originally good) turns its followers into extremists whose goals justify the means, as 16th century Italian politician Machiavelli wrote. But... is this true, fair, ethical?