The Greens have their issues, sure, but I feel like they're a lot more focused than National or Labour who's goals basically just seem to be 'do whatever it takes to stay in power'.
Oh, and the OP's analysis of the Greens is shit. Having subscribed to their newsletter I happen to know that they do A LOT of what they claim to for the environment. Or at least do their best to, which is all you can expect.
Also, 'socialist party that agrees with everything Labour does' is actually not a legitimate criticism of the party, if that's what it was intended to be. Firstly, it's wrong, secondly, so what if Labour and Greens sometimes (or even often) agree? Are parties not allowed to agree on things? You should be criticising the policies they agree on (if you find them disagreeable), not the fact that they agree.