Dortmund's handing over the title to Bayern Munich shockingly on the final match week was unbelievable to me as well. However I don't think Dortmund board are mad at this situation too much. I mean Terzic wouldn't get sacked for this. Because Dortmund's main target in this season was never to win the Bundesliga title. Maybe they got too close to doing it thanks to Bayern Munich's making many mistakes. But this was going to be extra effort by Dortmund if they made it.
This season has been successful. And however, Dortmund's failure to win the title this season they will regret very much. because after all, they actually have a chance to be victorious. However, because the previous matches were not optimal so Bayern could be taken over again. This will definitely be a very valuable lesson for them.