My Way Or The HIGH-Way!
In parshas Pinchas, the Torah has a census of Klal Yisrael, which was at the end of the 40 years in the desert. We find discrepancies between these numbers and those from parshas Bamidbar, which was at the beginning of the 40 years. Shevet Shimon had the biggest difference of numbers, the only shevet numbering losses in the tens of thousands. Based on this, Chazal say that the 24,000 who died in the plague at the end of parshas Balak were all from shevet Shimon. In addition, when Moshe blessed all the shevatim, he left out Shimon, only hinting at them, highlighting the disappointment with them from the recent tragic event.