I started the series feeling that way, to be honest. But the Blues were a fun team to watch, and they had some storylines that grew on you. Mostly Binnington and the turnaround from Jan 1st. They're a likeable team, and I was actively cheering for them by the end.
That was it for me too. I don't hate the Bruins, but I like rooting for the underdog and/or some "feel good" stories in the Finals, which seemed to be heavy for the Blues:
-The team and it's fanbase have never won the Cup
-No one on the team had ever won a Cup
-Going from last place to the Finals
-"Interim" coach
-Not exactly highly touted goalie coming from nowhere to being a key contributor
-Guys that have been around the block a few times like Steen and Bouwmeester finally winning a Cup
-Maroon allegedly turning down termed offers to take less money for one year to play in his hometown and close to his family