So, I'm not just talking about the pixel brushes. I can't get smooth lines to save my life and it's especially difficult to do details. I'm working with 2.8, and am updating as soon as possible. I'm relatively new to Krita, is there something I'm missing or what? And yes I am using the smoothing option in the Tool Option panel.

Uhm, yes, improved anti-aliasing was one of the big features of 2.9 The last build of 2.9 is 2.9.10, see if you can get it.

We'll be releasing the first alpha builds of 3.0 soon as well, hopefully with portable builds for linux, windows and osx at once.