system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout] Which Vault experiments were the most inherently cruel, the most disastrous and the most harmless?

Note that "most inherently cruel" and "most disastrous" are very much two different categories here, as in many cases the horrific end results of certain experimental Vaults were not necessarily intended to happen by the designers; for instance, Vault 112 was not *meant* to end up as an IHNMAIMS-esque scenario, and simply devolved into one due to Braun going insane and power-mad over a timespan of centuries.

And for "most harmless", I do *not* mean to include the handful of Vaults that actually functioned exactly as advertised; I'm looking for one(s) where there *was* an experimental gimmick, but it was actually relatively benign compared to some of the others.
gpt
The most inherently cruel may have been Vault 12, which was designed to let in radiation from the outside, causing all of the inhabitants to either die or become ghouls. Another candidate for this title would be Vault 87.

Vault 87 probably had the most disastrous results, since it was intended to be used for testing F.E.V., which directly led to the creation of East Coast Super Mutants.

The most harmless vaults, in terms of outcome, were Vault 21 and Vault 101. Vault 21 was filled with compulsive gamblers and designed to have a society built around gambling. Vault 101 was meant to be controlled by an Overseer with absolute power and never opened to the outside world. While we don't know their exact histories, we know that 200 years after the War, both Vaults had opened and contained thriving populations.