If you've ever developed plugins for the Minecraft server software Spigot, you can probably come up with a list of questionable API behaviour and design choices made by Spigot fairly quickly. Pain points that have made your experience with the API unpleasant or at the very least inconvenient at some points during development.

It is very likely that you were taught the same lesson as me when you first started learning Java: the benefits of using the JVM.
Usually, that lesson is just a very brief and general description of Java’s well-known cycle: Write source code, compile to bytecode, run anywhere. Thanks, JVM!