Picking up the phone to call someone. I don't mind receiving calls, but if I have to call someone, it is a hurdle to overcome. I think it stems from not being able to make people understand what I want for some reason.
An example - calling the doctors office:
Office: Hello, how can I help you?
Me: I'd like to make an appointment with the doctor.
Office: Is it an emergency?
Me: No, just a routine annual exam.
Office: You're not having an emergency?
Me: No.
Office: Let me get someone that can help you. (I get put on hold for 10 minutes)
Office (different person): Hello, can I help you?
Me: I'm calling to make an appointment with the doctor.
Office: What times are good for you?
Me: Monday and Friday mornings.
Office: Let me check to see what's available (put on hold for 5 minutes).
Office: I'm sorry for the wait. The doctor doesn't have any morning appointments available on those days. We could book you on a Tuesday.
Me (sighing inwardly): I can only come on Monday or Friday mornings.
Office: Please hold.(another 5 minutes)
Office (another person): Hello, how can I assist you today?
And it starts all over again.