It's because of how the system is setup to be g in with. Said item has a drop rate of let's say 1 in 100 times it will drop, but the problem with that whole system is that mathematically speaking you could do the thing 50 times a day for 10 years straight and always end up being in the 99. Because it's not 1 in 100 times you do it, but 1 in 100 downs period, damn system is setup like the lottery.