[BigJono]

I'm surprised this is the first one.

How about the null coalescing operator that literally has zero use outside of encouraging an anti pattern in failing to disambiguate null and undefined at the earliest possible opportunity?

How the fuck did that ever make it into the language?

Some of the upcoming proposals are absolutely ridiculous too. A lot of these are ideas that would be fine for niche use cases, but the proposal itself has examples so stupid that they should be shot down immediately because the person doing the proposal doesn't know what the fuck they're doing (e.g. the ridiculous jsx example in the 'do' operator proposal where for some reason we now want to shoehorn a block of procedural code into a 50 line declarative expression instead of just using a basic one line ternary operator that has been in the language for years).