In 2010, one of the many decisions Stan Bowman made when faced with a cap crunch was to trade goaltender Antti Niemi to San Jose, allowing him to match San Jose's offer sheet on RFA defenseman Niklas Hjalmarsson.
Fans hated that decision, Niemi had just won the Stanley Cup and was a large factor in the Blackhawks sweep of the San Jose Sharks in the Western Conference Final, while Hjalmarsson was young and unproven. Also, the Blackhawks then needed to call up the unproven Corey Crawford from Rockford to take Niemi's roster spot.
Fast forward to 2014, the Sharks are struggling and Alex Stalock might have stolen Niemi's roster spot. Hjalmarsson added a second Stanley Cup in 2013 and an Olympic Silver in 2014 and ranks 30th in franchise points by a defenseman (as of 11/11/14). The unproven Crawford now ranks 5th in franchise wins, behind Tony Esposito, Glenn Hall, Ed Belfour and Jocelyn Thibault. Crawford won the Jennings Trophy and Stanley Cup in 2013, Conn Smythe Winner Patrick Kane said Crawford deserved the award more than he did and Crawford was invited to Team Canada's Olympic training camp (he was cut from the final roster).
If Stan Bowman had done what the fans had wanted in 2010, the Stanley Cup and Jennings Trophy would not have made their way to West Madison in 2013. Hjalmarsson-Oduya would not exist, and therefore Sweden's Olympic Silver would have been far less likely. Crawford would have been sent somewhere else or still be in Rockford and therefore the Blackhawks would not have someone rapidly ascending the franchise wins list.
Stan Bowman clearly knew what he was doing and the armchair GMs were wrong. You are not an NHL GM, you do not know better than them.