The Watchtower has promoted 6 different and contradictory explanations of what “this generation” refers to. Many JW based their life choices on the generation doctrine that Armageddon would arrive before all those born prior to 1914 had died. Can an organization that makes such critical errors rightfully claim they alone are directed by God? Did Jehovah gave them the idea or did they come up with it on their own? Jehovah does not change and yet changes are coming fast and furious. 
Read in details at http://www.jwfacts.com/watchtower/generation.php#2010
Reasons We Left The Watchtower 