I am looking for an explanation of why answering omen after a single brochu is Meguna but not after a group of Bruchas. What is the explanation behind this . I know there is Divre Kabalah and Sodos hatorah in every word Chazal tell us but there must be a simple reason to this so that us simple people could understand. Thanks
At the conclusion of a set of blessings, one may answer "Amen" to his own blessings because the purpose of his "Amen" is clearly to indicate the conclusion of the set. On the other hand, answering "Amen" at the end of a single blessing looks like haughtiness, because he recites a blessing and then after his own blessing he says, "May it come true!" ("Amen").
After a blessing for food or for the performance of a Mitzvah, it is not only "Megunah," but it is also forbidden to answer "Amen" after one's own blessing, because "Amen" acts as an interruption between the blessing and eating, or the blessing and the performance of the Mitzvah (Mishnah Berurah OC 215:1).
Yisroel Shaw