Worst review was my first review. I went through several iterations of my first paper with my supervisors - it took a lot of editing as I couldn't write. However, we didn't rush it and it was fairly good by the time we submitted (to JAM). The paper was desk rejected by one of the editors and the editorial comments were unfair and downright nasty (comments like: poor quality research, adds nothing to the field etc). As a young researcher just finishing my PhD, it really knocked my confidence and it took time to build the courage to submit elsewhere. However, after encouragement from my peers and supervisors we resubmitted to a top journal in the field (Food Microbiol). This is now in my top 10 most cited papers (145 citations - https://scholar.google.co.uk/citations?user=tyLC9iEAAAAJ&hl=en) and I am proud of it. I had a horrible introduction to the peer review process but it taught me a lot (e.g. how not to review) and, the good news is that, I have never experienced a review quite as bad since (well maybe I have but I probably have thicker skin now!!).