In March 2014, I posted on LessWrong an article called "Two arguments for not thinking about ethics (too much)", which started out with:
I used to spend a lot of time thinking about formal ethics, trying to figure out whether I was leaning more towards positive or negative utilitarianism, about the best courses of action in light of the ethical theories that I currently considered the most correct, and so on. From the discussions that I've seen on this site, I expect that a lot of others have been doing the same, or at least something similar.
I now think that doing this has been more harmful than it has been useful, for two reasons: there's no strong evidence to assume that this will give us very good insight to our preferred ethical theories, and more importantly, because thinking in those terms will easily lead to akrasia.
I ended the article with the following paragraph:
My personal experience of late has also been that thinking in terms of "what does utilitarianism dictate I should do" produces recommendations that feel like external obligations, "shoulds" that are unlikely to get done; whereas thinking about e.g. the feelings of empathy that motivated me to become utilitarian in the first place produce motivations that feel like internal "wants". I was very close to (yet another) burnout and serious depression some weeks back: a large part of what allowed me to avoid it was that I stopped entirely asking the question of what I should do, and began to focus entirely on what I want to do, including the question of which of my currently existing wants are ones that I'd wish to cultivate further. (Of course there are some things like doing my tax returns that I do have to do despite not wanting to, but that's a question of necessity, not ethics.) It's way too short of a time to say whether this actually leads to increased productivity in the long term, but at least it feels great for my mental health, at least for the time being.
The long-term update (three years after first posting the article) is that starting to shift my thought patterns in this way was totally the right thing to do, and necessary for starting a long and slow recovery from depression. It's hard to say entirely for sure how big of a role this has played, since the patterns of should-thought were very deeply ingrained and have been slow to get rid of; I still occasionally find myself engaging in them. And there have been many other factors also affecting my recovery during this period, so only a part of the recovery can be attributed to the "utilitarianism-excising" with any certainty. Yet, whenever I've found myself engaging in such patterns of thought and managed to eliminate them, I have felt much better as a result. I do still remember a time when a large part of my waking-time was driven by utilitarian thinking, and it's impossible for me to properly describe how relieved I now feel for the fact that my mind feels much more peaceful now.
The other obvious question besides "do I feel better now" is "do I actually get more good things done now"; and I think that the answer is yes there as well. So I don't just feel generally better, I think my actions and motivations are actually more aligned with doing good than they were when I was trying to more explicitly optimize for following utilitarianism and doing good in that way. I still don't feel like I actually get a lot of good done, but I attribute much of this to still not having entirely recovered; I also still don't get a lot done that pertains to my own personal well-being. (I just spent several months basically doing nothing, because this was pretty much the first time when I had the opportunity, finance-wise, to actually take a long stressfree break from everything. It's been amazing, but even after such an extended break, the burnout symptoms still pop up if I'm not careful.)