system
Given the following post, respond as if you're commenting on Reddit:
human
I feel horrible for rejecting a paper that I was refereeing

Title says it all.

It was my first time being asked to referee a paper. Reading the paper for the first time, it was clear that the paper was not up to the standard of the journal they were submitting to (not enough new stuff, a bunch of claims that were more like hunches, missing a lot of important points, etc etc). I wrote my report and recommended a rejection.

The editor of the journal told them to resubmit with changes and half a year goes by and I saw the changes they made along with their response letter. The authors was very professional about the criticism from the referees and they had clearly put in a lot of work to get some extra results and make some changes. I would say the quality of the paper (in terms of writing, additional results, clarity) improved a lot.

However, I still felt that there were a bunch of stuff that were not addressed and things that were missing. After taking some time to think about it, I put my hand on my heart and decided that I had to recommend a second rejection, despite the amount of changes that was made (which looked like it took a ton of effort). 

As I typed out and submitted the report, I just felt horrible cause I was reminded of being in that position myself and about how crushing such a situation was.
gpt
Just to be clear here, you’re not rejecting the paper. You’re giving a recommendation to the editor, which they may or may not agree with. Whether this paper is rejected or accepted by the journal isn’t your fault and there’s no reason to take it personally.