I've been enjoying a featherweight alternative to log levels, made possible by org-mode.
Try this the next time you write a little throwaway command-line utility script:
Step 1: Add asterisks to the front of your printf traces.
Step 2: Tee your STDOUT / STDERR to a file named log.org
Step 3: Open the log file in org-mode.
Step 4: Rejoice!
Optional: You can tail the logfile with M-x auto-revert-mode.
This illustration uses a Github scraper as an example:
This is no substitute for real structured logging, of course :)
That is all.