time, time, time (-based classes and objects)
Someone complained, looking at the beta version of some new reports, that the “when” field was too precise. They didn’t need “17 days and 6 hours ago,” “17 days ago” would do. I was doing this with Sean Burke’s Time::Duration, wrapped by my own Time::Duration::Object, which just turns a number of seconds into an object with methods based on the functions provided by Time::Duration. It’s been a very useful module, but I never noticed that it had a major bug.