Smile! It's a terrorist attack!

A "selfie" is a photo taken at arm's-length by a cell phone or other digital device, and then (more often than not) posted on social media. A selfie device has been invented to stretch the distance between the subject and the camera. There has even been a song called "#selfie" (that once heard, can never been unheard).

During a hostage crisis in Sydney, Australia on Monday, two hostages lost their lives. The manager of the café that was under siege grabbed the gun from the gunman and wrestled it away from him. The manager, Tori Johnson, was shot and killed, but that act allowed some of the others to escape, according to London Evening Standard. The second victim, Katrina Dawson, was a mother of three, according to The Telegraph.

That hasn't stopped people from posting selfies from the site of the tragedy.

If you aren't aware of how common and, at times, selfish selfies are, let's look at some of the submissions to the website Selfies at Serious Places.

The backlash got to one guy (above) and he issued an apology via the website: "I'm one of the people on your tumblr blog, and I have to say you made me realize how much of an idiot I made myself look. I've had people messaging me and calling me stuff, all of which I obviously deserve. I know you probably think I'm just an idiot who is willing to put pictures like that on the internet, and you're not too wrong. You've really made me think about it, and I'd like to thank you for that."

A year ago, a woman received some serious bad vibes from the public when she snapped a photo in front of the Brooklyn Bridge... as police talked a suicidal man into not jumping.

Selfie-takers, the internets are displeased with you.