Working with you has been quite a learning experience.
Number One, you were somewhat difficult, but that's because we had to collaborate through our advisors and it was like a game of tin-can telephone. When we talked later without them getting in the middle, I was impressed with your work ethic.
Number Two, you were a misogynist jerk and I couldn't work with you. I'm glad someone else in my group was able to work with you and publish a nice paper. But I hope you get over your sexist tendencies (or burn in hell! Jerk!).
Number Three, you were awesome. You singlehandedly restored my faith in Science. I feel bad that our paper together did not end up in the best journal ever, since it was the most fun I've ever had doing science.
Number Four, you have been a lot of fun but also a struggle. And I think I have been, too, so it's only fair. We speak different languages, scientifically, and I think in spite of that we've done pretty well and had a mostly good time doing it. I hope our paper together will end up in the best journal ever (as we hope for every paper but especially now since I need one of those to get a job).
Number Five (and one other like you), I'm now regretting that we tried to work together. It will be a line on my CV, but I have learned an important lesson here, which is that it's not a good idea to collaborate with everyone who asks. I just hope nobody ever asks me to defend your work because I will have a hard time explaining that you never showed me a draft of the paper before you sent it out. (Without sounding Negative, that is.)
Number Six, I think it is sleazy that you keep editing the manuscript to add in superfluous citations to previous work from your lab that is only distantly related to what we're writing. You delete references to my previous work that are actually essential, and you put these other references in that undermine our interpretation of the current data. I am frustrated by working with you, but I have to put up with it or negotiate around it. I know it would be easier to just go along with you in the short-term, but we might pay for it when the paper is in review. So I have to think carefully about how to bring you around to my way of thinking. I know you are thinking you will continue to do the same (or just threaten me, because you know that will probably work, too).
Dear Collaborators, sometimes you make me love science and sometimes you make me really wish I were better with computers, so I could maybe sometimes do a whole project start-to-finish without being at the mercy of miscommunication flare-ups and other people's schedules and egos. My own scheduling and ego issues are enough, thank you very much.