Giving credit

How would you do if someone used something you created without giving you credit? I would be really upset and that person would have to explain to me why they felt the need to do what they did. This kind of stuff happens on jobs all the time. I remember when I worked for a retail company and you had to come up with ways to minimize the work load. Especially, when it came to putting out inventory and stocking the shelves. One way I thought was to make the stock room more organized. So, I suggested that we put all of one kind of product together and so on. Before, we knew it, the space and area was cleaned. When the head guy came down, my manager told him that she decided to make things easier. He was very impressed. Not only did she get a recommendation, but she also got a bonus. I have never been one to hold my tongue to often especially when I was younger. I let her know that what she did was wrong because it was my idea. It would have been okay if she had taken some credit but she took all the credit. After that whatever ideas I had, I keep to myself or I just did it. I did not care about the recommendation or the bonus, although the bonus would have been nice. What she did was change the relationship we had not only as employer and employee but we were also friends. When you take credit for someones else work, you are not giving them the chance to shine. To me that is one of the most selfish thing a person can do.