The incident at קברות התאווה where the people complained about lack of meat and watermelon, was very telling. Hashem answered their request by sending the quails.
It was bad enough that they were unappreciative of Hashem’s kindness in the desert. The מן provided them with all of the nourishment that they needed. But what was worse was the way they collected the quails. Rabbi Soloveitchik comments that they gathered the שליו in piles and acted like mad men.
Judaism hates hoarding, avarice, and greed. People who believe that security comes with amassing wealth are nothing but fools. The sin of קברות התאווה was one of greed and desire. The important lesson here is that our real security comes only with our complete reliance on Hashem. Anything else is vanity of vanities. Shabbat Shalom