It’s possible that your boss won’t take immediate action like the reaction above—but will make it clear that he or she isn’t exactly happy about your resignation.
Maybe, for example, she’ll mutter a curt, “Thank you for letting me know,” followed by two weeks of obvious displeasure or denial that you’re leaving—through gruff comments (“You know, you’re really leaving us in the lurch”) or a refusal to interact with you more than absolutely necessary.