Sometimes the best WTFs don't come from without; they come from within. If you think back across the history of your career, you've probably had your share of red-faced, forehead-slapping moments from doing something stupid. You've got some coming up ahead, too. And if you've never made an embarrassing professional mistake, congratulations, you're an oblivious "Expert."

Dan O. was enjoying the fruits of working for a dot-com venture in early 2001. Well, like most dot-coms at the beginning of the century, Dan's went bankrupt. Maybe they were ahead of their time, maybe they were big dreamers, or maybe it was the fact that a client that represented 80% of the company's revenues dried up.

Concerned for its employees, the company did the most responsible thing they could to inform their staff that they'd be losing their jobs; they packed up everyone's computers one night. When the staff showed up the next day they were greeted by unattached monitors, keyboards, and mice with cables dangling on their desks. The confused staff began collecting their personal belongings from their desks, and Dan contemplated his career. A few developers that weren't aware of the company's financial situation were trying to figure out where their computers were.

HR started rounding people up for exit interviews, and Dan began contemplating his situation. He went through the stages we all go through when leaving a job: fear, mild hunger, frustration, grandiosity, and excitedness (for a little time off). Some employees joked about how they'd spend the $0 they got from their (nonexistent) stock options. "I'm going to Disney World! Dot com, I mean." "I'm going to get some free literature about what Jesus can do for me!"

Dan got a few interviews in the following months. He was experienced for a Junior Programmer, having built client-server apps with Delphi for years and developing a decent body of knowledge about different database platforms. He'd messed with MySQL, Java, PHP, and even Parity's VOS (a telephone application language). He even had some light exposure to older technologies like FoxPro, Clipper, Paradox, and dBASE II.

Three months of no income later, times were getting tight, but he had a good feeling about an interview at a big healthcare company. They were looking for a Delphi or VB coder, which wasn't his dream job, but he really needed the work. His interview was going smoothly and he could tell that he was building a solid rapport with the interviewer. Now to just ride this out until I get an offer, he thought.

The interviewer asked, "Do you have any experience with DB2?"

Dan hesitated for a moment, pondering how to answer the question. Despite working with several different database server products, he'd never even heard of DB2. Does she mean dBASE II? he wondered. The flat-files used by dBASE II use .db2 as a file extension...

The correct answer would've been "Well, I haven't had a chance to use DB2 yet, but I've worked with other relational database systems like Oracle, Microsoft SQL Server, and with various flat-file databases going back to my early teens."

He didn't give the correct answer.

Instead, he launched into a five minute lecture about why a company of their size shouldn't use flat-file databases, how a RDBMS would suit their needs better, and why a woman of the interviewer's size shouldn't wear horizontal stripes. OK, I'm lying about the last one, but with the impression he made, it probably wouldn't have made him look like much more of a boob. When he got home 20 minutes later, he looked up "DB2" and found out that it was fundamentally different than dBASE and he really should've listened to his conscience.

He learned a lesson, though, and it's that in an interview, you should never try to "school the interviewer." You'll either bore, contradict, or offend them. And for the love of god, if you find yourself talking about something you don't understand, shut the hell up and don't try to talk your way out of it.