We inherited many traditions and routines from our parents subconsciously. For example, a popular one for the Chinese would be the prohibition to sweep the floor at night, since it will drive good luck away. The answer tries to rationalize why we do or don’t do certain things.
The Israelites had their own traditions. For example, why do we take a rest on the Sabbath? Because YHWH creates the heavens and the earth on six days and took a rest on the seventh day. Hence, we take a rest on the seventh day, as well. Why do we eat unleavened bread on the Passover? To remind us that we left Egypt in a hurry (such that we didn’t have time to wait for the bread to be leavened). What’s interesting for me is the reasons are usually theological and covenantal. The basis of doing or not doing certain things came from the covenant relationship between YHWH and his people. So usually the reasons are not arbitrary.
A perhaps amusing tradition is found in Exo 33.6: “And after leaving Mount Sinai, they stopped wearing fancy jewellery.” Why did they do so? Because YHWH told them to do it (v. 5). And why did YHWH told them to do it? Because jewellery was associated with the idolatry that they did when they made a golden calf for themselves, which they made using the jewellery.
So, if their children asked, why don’t we wear jewellery, their parents could answer, “To remind us that we have betrayed YHWH by making a golden calf for ourselves and hence to remind us not to repeat the same mistake once again.” As Apostle Paul put it, “What happened to them is a warning to keep us from wanting to do the same evil things.” (1 Cor 10.6)