Lisa,
frustration is the first step in the anger cycle, which can lead to anger then rage. There are 2 ways of dealing with this:
coping thoughts and/or assertive counter techniques.

Coping thoughts are an internal dialogue that we use to do a "reality check". We look at our unmet expectations and determine if it is a "reasonable expectation". During this reality check we attempt to eliminate assumptions (trigger thought) that focus on blaming others, magnifying the problem and devaluating the other individual's character and their universal rights.

Universal rights are complex but some of them are:
(these are communications rights)
Right to express my wants, needs, thoughts, opinions, ideas & feelings (anger, sadness, joy, discouragement, frustration, etc.)
Right to be illogical...."I know it doesn't make sense but this is how I feel".
Right to be confused..."I don't understand"

Assertive counter techniques:

Acknowledgement
Repetitiveness
Getting information
Responsibility consequences
Main issue (refocusing)
Expressing needs
Negotiating
Timeout(withdrawing)
Let it pass (do not take the bait)

Do not take criticism personally as a reflection of your value as a human being. Even if a $100 bill is stepped on, it's still worth $100.

I was my fathers caregever and he expressed the same frustration and complaints EVERY time we spoke. I had to put it in perspective of one of gratitude that it wasn't me going through what he went through.

Being abused shouldn't be part of the equation - you are NOT the enemy.

Also, men in general express their fear and pain with anger. Whereas women tend to be more open and direct with their feelings. It's more of a cultural thing.

Cancer support groups can often help you deal with these issues as well - ask your hospital social worker or check your local newspaper for support groups.