Knowing that someone out there already predicts my behavior perfectly
The halting problem shows that perfect prediction is impossible if you don't simulate the whole system. On the other hand there are plenty of cases where pretty good prediction is possible.
Observing myself act in ways I never intended to act, whether beneficial to me or not
When it comes to acting in way you don't intend to do, flirting is a good example. I remember an experience I was sitting next to a beautiful girl in a lecture.
We had good "chemistry". One time I look at her breast and she immidiately touched my arm and then automatically said "sorry". She had no conscious knowledge of the fact that she touched me in response to looking at her breast, so she excused her behavior.
I also caught myself one time touching her and immidiately excusing myself where I didn't consciously intend to touch her.
I don't think that such actions we take outside of our conscious awareness mean that we don't have free will.
Observing my arms/legs/mouth move as if externally controlled, and being unable to interfere
If you cut my nerves that control my arm and put in electrones to control my arm I don't think that would mean that I lack free will.
When it comes to psychological control, part of free will is the ability to give up control over your arm. I get more annoyed by my personal inability to give up some forms control as I would see that as given up free will.
Given the spike in free-will debates on LW recently (blame Scott Aaronson), and the usual potentially answerable meta-question "Why do we think we have free will?", I am intrigued by a sub-question, "what would it feel like to have/not have free will?". The positive version of this question is not very interesting, almost everyone feels they have free will most all the time. The negative version is more interesting and I expect the answers to be more diverse. Here are a few off the top of my head, not necessarily mutually exclusive:
Epistemic:
Psychological:
Physical:
For me personally some of these are close to the feeling of "no free will" than others, but I am not sure if any single one crosses the boundary.
I am sure that there are different takes on the answers and on how to categorize them. I think it would be useful to collect some perspectives and maybe have a poll or several after.