When G-d instructs Avraham to leave his ancestral home, He promises Avraham great wealth, success, and fame. G-d then says that “I will bless those who bless you and those that curse you will be cursed” (12:3). It would seemingly be more congruous to say, “I will bless those who bless you and curse those that curse you.” Why is the terminology reversed for those that curse? And why is what others think or do a part of any calculus?
The Vilna Gaon suggests that G-d commits to blessing those that practice positivity and in fact blesses them even before they show any inclination to bless others (this is why it is worded accordingly, in that order). Conversely, those naturally mired in negativity in the first place and predisposed to cursing others would warrant being cursed themselves.
Blessings are such an integral part of our lives because they create positivity, both for those that give and for those that receive, and exponentially increase the goodness shared in the world.