Reporting bugs you have encountered is critical for improving the site and giving everybody a happier experience. Tracking down the cause of a bug, however, is not always an easy job, so here are a few tips to help clarify the issue for us:

What?
What exactly happened that led you to believe this was a bug? What was the error message, what happened unexpectedly, or what looked out of place?

How?
What were you doing that led to the bug? What steps did you take, or what product or data were you trying to look at? Details, details :)

Where?
Which page did you experience the bug on?

When?
When did it happen? Day/time?

How often?
Were you able to repeat the error, or did it happen once and never again?