I get the whole RNG aspect of it, but come on. I just dropped somewhere around 4M silver to take an amulet from 12 to 16, and I'm still at 15!! And the game has the nerve to recommend that I buy the silver pack! 

I know, "it's all random", "tough sh*t", "tell that to the one-legged man so he can bump it off down the road"...but 4Mil?! For 3 levels of upgrade!? I've grown to expect to spend 2M-2.5M to 16 a piece of 6* gear, but this is some RNG magic that shouldn't be in the game. If there is no limit to RNG, hypothetically, it is possible to drain your entire silver no matter how much you have.