>>It's possible to give feedback without burning bridges.

Unless you are a coach, and your job is to give feedback. I would advice a) Don't give a feedback ever. b) If you are in a situation and had to give feedback, always say something positive.

Very few people are genuinely interested in improving and largely use feedback as a mechanism to see how people judge their work, and here a negative feedback is simply used to mark up people as enemies.

There are people who are exceptions to this, but this really is the rule.