Also effectively (sadly): You can bad-mouth someone to your own manager, provided your manager is peers with your target. I've been in too many performance-re

Also effectively (sadly): You can bad-mouth someone to your own manager, provided your manager is peers with your target. I've been in too many performance-review manager meetings where someone under Manager A is up for promotion, and Manager B steps in and says "my engineer had a bad interaction with your engineer" and that's enough to put the promotion at serious risk. Managers are happy enough to effectively kill a promotion with a clean conscience by saying "let's re-evaluate this one in mid-cycle reviews". Sure, set this engineer back 6 months, a year, a year+, no worries all good.