I had to sit down for a tough sit-down with my project partner last week after they missed three major deadlines in a row and dumped their remaining workload onto my desk. I kept putting off the conversation for days because I was worried about ruining our personal rapport, but when I finally brought it up, my frustration overflowed, the talk devolved into mutual accusations, and we ended up barely speaking for the rest of the sprint.
Stepping into delicate interpersonal situations always comes with an element of emotional risk and unpredictable human reactions. You can plan every single sentence with the utmost care and practice your delivery for days, but individual moods and sudden shifts in room energy can turn the whole interaction in a completely unexpected direction.