I used to play WoW a lot and there is a popular activity there - farming rare drop mounts.
Most raid mounts have 1% drop chance - for example Invincible from Lich King 25HC.
And these are raids, you only get one shot per week per character. If you only have 1 character then it could take you literally years of farming to get those mounts. Most people have a big stable of alts by now though. And it's easy to share saves between them, so you don't have to clear whole raid each time.
If you have 10 characters there is a reasonable expectation to get some of those drops done after just a few weeks to few months.
Running those 100 times without seeing any drop is about 32% likely to happen. Fairly large chance. Lots of people get this, yet they still whine on forums from time to time.
Since millions of people play WOW and farm old raid mounts, even insane things like not seeing a drop in 1000 attempts did happened to some people. Or seeing a drop 3 times in a row which is exactly 1 in a million (three 1-100 dice rolls rolling 100 pts each time)