My greatest alcohol-related fear is that in a drunken stupor I'll text my boss and tell him to do all manner of anatomically impossible things to himself.
Textalyzer for iOS, like Gmail Goggles before it, offers you some protection against such social nightmares. The app allows you to blacklist contacts, requiring you to beat a series of coordination-testing games before you can reach out and verbally molest someone. This is a godsend if you're like me and constantly worry about texting embarrassing drunken messages to your mum, your ex, your co-workers or anyone else who you'd rather not see you at your worst. Which should probably be your entire address book.