Lost My Job Because Of A Joke Gone Wrong

I thought I was being clever when I sent out an email to my whole department with a funny meme about office life. The problem? It was also pretty mean-spirited and targeted one of my coworkers who's not exactly the most popular person around here. Everyone laughed, but it turned out our boss saw it too and she didn't find it funny at all. A few days later, I got the call no one wants: I was let go for making a hostile work environment. Sometimes you think you're just cracking jokes with friends, but you forget that your coworkers are also human beings who might take offense. Now I'm back on the job hunt and trying to find it in myself not to feel bitter about my mistake.