You Are Not Assertive
Instead, you tend to get very frustrated if people don't read your mind!
You may want to be more assertive, but when the time comes, you find yourself at a loss for words.
Try practicing what you'll say ahead of time, and try being assertive with little things first.

How Assertive Are You?
Are you good at asking for what you want? Or are you too meek? Or too forceful?