Speaking up in day to day life

Assertiveness is a skill that one can apply almost every day. Here's an example:

I moved my professional office (after 20 years in the same place) and went to Office Depot to order new business cards. I gave the clerk my old card so that she could order the same card stock and print style and color. I also gave her a typed paper with the new information on it that was supposed to be on the new card. I did the order two weeks ahead of my first day in the new office.....just in time to have the cards when I first saw clients there.

When I went to pick up my cards on the week of my move, I found to my dismay that they had simply duplicated the old card, so the cards had all of the old information and were completely useless to me.

I said, "I ordered cards with my new office address and these are printed with all my old information and none of the new."
The clerk said: "Did you give us your new information?"
This was a different clerk and she did what people often do when asked an assertive question: she blamed the victim.
"Of course," I said. "The new information was on a separate piece of paper. The clerk wanted to use the old card as a model for the stock and print, but the separate piece of paper was included with the order."
"Well, we'll just have to place the order again," the clerk said.
"I'm disappointed. I had wanted the cards for my business opening this week. I would like to get these sooner than the usual two weeks waiting time. I need them as soon as possible."
"I'll put in the request," the clerk said, "but I can't be sure that they'll be here any sooner than two weeks. I will put a rush on them, though."
"Thank you," I said and left feeling somewhat discouraged.

One week later, I went to Office Depot to check to see if on a chance, the cards were already there.

The clerk said to me, "Hi, how are you?" as she waited on the previous customer.
"You are going to determine how I am," I said, lightheartedly, "depending on how you answer a question."
The customer turned and said, "I'm curious, what is the question?"
So I told the customer how my cards had come in done wrong and it had only been a week, and I was hoping that the cards would be there and that would make my day. The question was, "Are my business cards in yet?"

The clerk finished with the customer and looked under the counter. "Oh," she said, "I was just going to call you. They came in this afternoon."

The assertive statements are in bold above. You can see that I wasn't angry, but simply assertive and the results were good ones. There was no point in being aggressive, as I have often seen people do, with the clerk, since it was not her fault. But making respectful "I" statements got the job done.