In Roman times, this was part of series of celebrations related to Cybele and Attis, representing a cycle of death and rebirth.
Requietio (26 March) was a day of rest. People probably needed it after the previous day (Hilaria).
Sometimes, it's just as important to know when to stop and rest, as it is to make an effort. Take the time to rest and recuperate, and you might notice things, and enjoy things, that you missed before. And even if you don't, isn't it nice to take a break?