Comment by foresterre

They're a bit verbose, the interfaces are slightly convoluted and some basic operations are missing from the standard library.

It's also a little convoluted to work with different types of data.

For this one, I wish they would have taken a bit more inspiration from other languages and spent the time to make it more readable.

That said, I generally like streams a lot, and they do reduce the amount of branching, and having less possible code execution points makes testing easier too.