Do you like being "put on the spot"? What about if it's at your job?

We all get asked to do things everyday that are not part of our normal routine. I get that. What I can’t stand is when you hear someone saying, “Oh, N_______ will take care of that.”, and it’s something that you have not had to do before. Or you get an email along the lines of “Oh, I hear you are going to be doing the such-and-such report.” Nobody comes to you and says “this is something we need your help on”, or “this is something we want you to do from now on.”

Am I the only one who gets bothered by this?