The holiday of Passover was made for people with OCD. Think about it; the massive cleaning, the counting of cups and plagues… Even the strict time lines involved in the baking of Matzo (the Matzo only has 18 minutes from the time the water and flour first mix until it is removed from the oven, or it is considered Chametz, or leavened, and not allowed for use on Passover). So imagine, after you’ve done all that cleaning and preparing, you now have to go around your house, the very night before the holiday begins, and purposely put out crumbs of bread!
Okay, this is where my OCD’ers have minor heart attacks. Why? How? Huh? Okay, deep breaths people. Here is why we do it (thanks to Chabad.org for the following explanation. You can learn more by clicking here)
The dispersal of pieces of chametz around the home prior to the bedikat chametz (ceremonial search for chametz on the evening before Passover) is not obligatory — the obligation is to search, not necessarily to find — but has become accepted Jewish custom. Based on kabbalistic reasoning, it is customary to place ten pieces of bread around the home before the search. On the eve of Passover, when the entire home has been spotlessly cleaned, it is highly doubtful that any chametz would be found in the home. These pieces which will now be “found,” will give us “chametz fuel” for the traditional chametz burning ceremony on the following morning. Otherwise, it is conceivably possible for the entire chametz burning tradition to be forgotten.
I hope this helps explain a little bit about why we do it, and why, in Jewish neighbourhoods on the morning of the eve of Passover you can smell burnt toast for miles!