What is the one thing you find odd about any programming language

In ruby, `unless` bugs me. Not that it's hard to understand, but the assertion that it makes code easier to read has always puzzled me. if !(x) was never all that complex, and saying it is hard for new programmers to understand has always troubled me.

In Java, the "write once, run everywhere" is true only if you are in some boundaries.

Java Preferences API are a classic example of this false myth, since e.g. on MacOS it behaves differently than in Windows/Linux.

And ever heard of Native Runtime? If you want to create a native runtime, you just need to do this on the target platform.

So this is very odd to me. GoLang went much further, doing true cross compilation