Staying too long. If your goal is to grow in responsibility, title and compensation, the most important thing is to have a boss that has the inclination and authority to develop your career and promote you, when appropriate. If you don't have that, you need to make a move.
I'll start. I had been chatting with a coworker online while at work — using a bit of coarse language. Shortly before leaving, I copied and pasted some marketing copy into the CMS for the page I was working on. I didn't check my work and went home for the weekend.<p>Got a text Saturday morning that something was off about our "For Prospective Students" landing page (I was working on the new website for a Private Catholic College). Navigated there, and stood staring in disbelief as I read my own words calling a certain friend of mine a certain derogatory name or 4 under the heading "Why Choose Us?" Turns out, I thought I had added the Marketing copy to the clipboard, but must've accidentally copied and pasted a fraction of my damning convo instead.<p>Lesson Learned: ALWAYS check your work, no matter how long you have been building websites or anything public-facing. It was such a dumb mistake. I didn't end up fired, but got a stern reprimand from my direct supervisor. Months later, the President of the school confided to me that he found the incident fairly hilarious, and somewhat troubling. Hoo boy.
there was a tax issue in our shopping cart software that only occurred in florida. I googled for an address in florida and put in a few test purchases.<p>Long story short, I shipped a thousand dollars worth of networking equipment to Disney World.
I once fell asleep at a customer facility. We had been doing 12hr days and it was a weekend. No one was there. Cafeteria was closed so no coffee. So I decided to find a quiet spot to nap. Needless to say I got a call from my boss's boss's boss. Also, I was told to not bill that day. Despite being salaried with no overtime and having reached 40hrs in the first few days.<p>It wasn't the same after that. Never let your boss or coworker discover how little you care about work.