In my locality, people have the belief that besides some actions that invalidates fasting there are some other actions too that makes someone's fasting weak or lessen in reward or if the fast without committing any sins is 10 then if you do those certain actions your fasting will go down i.e. 6/7 etc. depending on the merits of the action. By "some certain action" they mean some particular sins such as uttering bad words, slandering someone, quarreling, watching blue movies or pictures, stealing, sleeping much than the norms of sleep cycle, frequent spitting, forgetfully drinking water etc. So far these are the actions that they believe will make someone's fasting lessen or will make your fasting down grade in the scale of strong fasting to invalid fasting (in between).
Is this authentic according to the Islamic rulings? I'll appreciate if you answer this Q. in a elaborate manner like quoting hadith, Quranic verses, scholarly statements, consensus, agreement and some other aspect regarding this.
