Yoma 22-23 – two incidents, first one kohen knifing another to death, then one breaking a leg. In first case, the father notices that the son is not yet dead and thus the knife is still tahor …. that it got to that people cared about bein adam l’makom and were not sensitive to lives …
the system was changed from competition to lottery after the second, leg, incident. After the first grave incident, committed out of anger, people understood the averah and possibly did teshuva. The second one, an “accident”, would not lead to teshuva, so the Talmidei Hachamim closed the games.
there are other halakhot where inability to connect the dots makes an avera more serious (for example, insulting people). Shows that we need leaders to step in specifically when people cannot connect their behavior with the damage they are doing …