Maybe this is obvious to everyone else but in Steven Universe, ep 38 “The Test…” I think garnet purposefully rigged their test to fail. Pearl’s test was so easy it couldn’t fail; amethyst made hers a bit difficult but that with enough thinking, she knew Steven could sail through. But Garnets? Random fire. Crushing obstacles. They wanted Steven to see how much the gems were concerned for his well being, and that the original “test” wasn’t to degrade him but rather to make sure he could be kept safe. What Steven really learns from the test is how to see the Gems perspective and put aside his own intrusive thoughts.

That’s why at the end they say “I knew you could do it.” They know how perceptive and caring Steven is, and that he would be able to reevaluate his view and make sure the crystal gems knew how much he appreciated him…