We all know the moment. Your friend's phone is sitting, unprotected, unguarded, just waiting to be used for a little mischief. You know you should take this opportunity to do something with it, but inspiration rarely hits until it's too late. Of course you could snoop through their texts and private Facebook messages, but that's a little too sociopathic even for Evil Week. Instead, here is some of the best mayhem you can cause with just a few minutes on someone's phone, with far less chance of ruining your friendship.

Mac: We often think of autocomplete as being most useful of phones. MacWorld points out that it's pretty helpful on the desktop if you use it right.

Lifehacker reader Jordan loves the easy browsing that enabling auto-completion in Firefox provides, but found it just didn't work for some sites. The fix? Removing bookmarks with "www" stuck at the front.

Gmail Labs adds a new feature to save time when composing messages—it can now suggest contacts based on the groups you email most often.

Google Image Search joins Google's web search and Google Video in offering suggestions to auto-complete your search, often with a "wallpaper," "logo," or other popular terms. Don't like the clutter? You can turn it off.

Gmail Labs has released a great new Search Autocomplete feature today that can give search suggestions for all kinds of Gmail searches, from simple search-by-contacts to more advanced search queries—like for specific attachments.

Previously mentioned LastPass—which adds web-based autocomplete for logins and forms with Firefox and Internet Explorer add-ons—has created several new bookmarklets to support auto-fill from any browser, including Google Chrome, Opera, and even Safari on your iPhone.As you can see from the video, all you need to do is login to your LastPass account (registration is free) and drag the bookmarklets to your bookmark toolbar. (If you want to use LastPass on your iPhone, you'll have to create the bookmark on your desktop and then sync it to your iPhone.) LastPass received an honorable mention in our Hive Five Best Password Managers very shortly after its release, and its quick development and impressive features have won over many more users since its initial release. The official Firefox extension and IE plug-in are both still better options when you're using those browsers, but for browsers that don't support add-ons, the bookmarklet support is a godsend. LastPassOpera, Google Chrome, Safari, iPhone, Opera Mini and more with Bookmarklets

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Auto-complete is one of those features that gets more and more convenient the more you use it—so losing it completely on a new system, or just new Outlook installation, can be a shock. The Tech Recipes blog details the process for hunting down, copying, and pasting your .NK2 file from system to system, saving you the trouble of re-training your email mind. For most users, the file can be found in your "Application Data" (XP) or "App Data" (Vista) folders, nested inside "Microsoft->Outlook." For help on actually editing and removing entries from Auto-Complete, check out NK2View. Outlook: Transfer AutoComplete Addresses to a New Computer

Google's Experimental Search section has added a feature that lets users enable auto-completion of search queries from their main Google pages. While certainly not a new function in the search world, "Keyword suggestions" can help you spell out hard-to-remember words like onomatopoeia and harness the searches used by other Google searchers to find what you're looking for. Unfortunately, turning on keyword auto-complete will turn off any other Experimental features you have enabled, such as keyboard shortcuts, and doesn't carry over to iGoogle home pages yet. For those who still use the streamline basic Google page, however, it couldn't hurt to try it out.

Google Experimental Search