Deployed a backup script on a new server, tested it manually — worked fine. Set up crontab, came back next morning, no backup. Turns out /usr/local/bin wasn't in cron's PATH so pg_dump just silently didn't exist.

Switched to absolute path and it worked immediately. Fifteen minutes of debugging for a one-character fix. I keep making this mistake every time I set up a new box. At this point I should just have a checklist taped to my monitor.