My insulin pump had a minor failure at school, but I had to go to the Emergency Room for it, and of course I fixed the issue before going. But the hospital I went to was a military hospital, which just had a random surge of patients come in (four ambulances, and people who failed their PT tests that day were also required to go in), which means that they took fucking forever to even see me. (not that I should've been prioritized over the people who actually needed help, but at least over the PT-failers, right?) And I myself was also drinking water and keeping track of my blood sugar too, so by the time they saw me, the problem had fixed itself. But that in no way stopped them from giving me an entire IV for one measly blood test, and upwards of 40 minutes between various med tech and doctors coming in to run the usual tests for high blood sugar. I literally could've just gone home from school and at least rested while I recovered.

TLDR: Docs took so long to see me, that my problem fixed itself and wasted my day

Bonus Tip: If you have options, never ever go to a military hospital