When someone I followed for whatever reason keeps showering posts that do not justify the time consuming clutter it causes in my feed merely for the sake of posting, I do unfollow, albeit always with a twinge of empathy for that person's possible hurt for me doing so.
Would be nice if every time one clicked the 'unfollow' button there was a popup field in which one could drop a notification to the poster as to why one decided to unfollow. Feedback provided this way would help posters shape the quality and frequency of their posts to a level where one would like to keep on following them.