I recently received two postdoc offers on the same day. I accepted one (verbally, in saying "I would like to accept this job offer", but I have signed nothing), but then some additional information came to light that I would not be happy in that role and the other was probably a better fit for me after all.
It is undoubtedly the case that I failed to adequately understand the pros and cons of each role before accepting one of the roles. I accept this, but it's also my first job, and frankly I have no idea what I am doing. If I had a better idea what I was doing then I would have been able to extract this information before accepting one of the roles. I accept that I have been fairly useless in this decision-making process and I am quite ashamed and horrified by it all (I'm not really sleeping and I've even had nightmares, as ridiculous as that may sound). Frankly, I just want it to end, but I want to make the right decision as it will have a profound impact on my life. And the right decision for me is to decline the offer that I had previously accepted and go forwards with this alternative one. At most as it stands I'll have cost them about 2-3 days of time. It's not as if I've kept them hanging for several weeks or months before finally backing out. I can already tell my would-be supervisor in the role I wish to decline is a very decent and kind person and I want to cause them them the absolute minimum undue difficulties and upset.
How unethical is it to decline an offer after accepting it (but without having signed anything)? How can I go ahead with now going back on my decision and let them know in the best possible way? Thanks for your help.