When a pre-commit hook fails (linting error, formatting issue, test failure), the git commit does NOT happen — it's aborted. A common mistake is to fix the issue and then run 'git commit --amend', thinking you're retrying the failed commit. But --amend doesn't retry — it modifies the PREVIOUS successful commit. If that previous commit was from yesterday's feature work, amending would: (1) merge today's unrelated changes into yesterday's commit, (2) lose yesterday's original commit message, (3) create a confusing git history where one commit contains changes from two different features, and (4) if already pushed, would require a force-push to fix. This is especially dangerous for AI coding agents that automate git operations.