How do I make good chimichurri? I've checked out several recipes and none of them really turn out right. They taste like well... parsley, balsamic vinegar, and garlic. No actual kick to it. Nothing special.

I toss the whole thing into a hand blender and serve it raw.

I'm not sure if I'm using the right chili. I don't have access to many American chilis, and am mostly relying on SE Asian ones. I also avoid alcohol, hence the usage of balsamic vinegar instead.

Am I missing some technique or secret ingredient?
A couple of ideas you might try: using half cilantro and half parsley, and adding some very finely minced raw onion. I also sometimes add a tablespoon or so of drained capers. Some people also add a modest amount of fresh oregano leaves for their resinous punch.