1. The reason for practicing certain customs of mourning during the period of Sefiras Ha’omer—from Pesach until Lag Ba’omer(the 33^rd day of the Omer)—is  that the disciples of Rabbi Akiva passed away during this period as Divine retribution for not treating each other with the proper respect. It is therefore not appropriate to enjoy extra happiness during this period (Shulchan Aruch and Mishnah 493).

2.    These customs remind us to distance ourselves from hatred, desire, arrogance and pride, and to acquire for our souls the traits of love, humility and peace (Kaf HaChaim ibid.).