לזכות עדינה בת שבע בת נעכא גיטל בתוך שח"י
1] Tears show that we are lacking. After the Churban, all the gates are locked except for the "gates of tears" - Tears get in because they demonstrate how much we lack.
2] We cry because we don't have the "keilim" to contain the pain.
3] Tears "sweeten" the strict judgment.
Can anyone cry about the Churban Beis Hamikdash?