Pure RNG is the worst thing ever.

[Pandastirfry]

What would you prefer: 10% chance of an item dropping at the end of a dungeon or completing that dungeon 100 times to get the item? I personally would prefer the 10% chance because that's possibly up to 99 dungeon runs I wouldn't have to do. You could argue "But what if it takes you more than 100 runs and still not get that item?" and I'll tell you "The odds of that are extremely low and only the lowest percentile of people would even come close to having such bad luck".

Uh... That has a name...gambler's fallacy

The odds of that happening are actually statistically LIKELY