Sometimes it's the littlest things that make for the most happiness. A few weeks ago I helped a colleague at the office who was tearing his hair out over what seemed to be bizarre, intermittent browser errors. The links in a document he was preparing sometimes worked, in other circumstances failed. After a bit of over-the-shoulder observation I suggested a few experiments, none of which enlightened either of us. Then I happened to look closely at his browser's address field, and spotted an extra "." after the host name in the URL. Hmmmmm! We removed the superfluous dot, and all his links functioned perfectly.
Some days later the same fellow complained about a frustrating inability to paste into a particular web page's text field. I watched him try to summon a pop-up menu — none appeared — and agreed that the standard Edit menu for the page had "Paste" grayed-out. "Try typing a control-V," I suggested. His jaw dropped when it worked. "That field you're trying to put text into is part of an applet," I explained, "and perhaps the programmer didn't add menu support but did keep the keyboard shortcut active."