It sounds like your inner dialogue is pretty vicious. Do you have a tendency to expect perfection from yourself and then beat yourself up the instant you deviate from that perfection? Most women have been programmed that they are supposed to be perfect and when they don't quite measure up that they are then unworthy, unloveable, or inadequate.
The most painful thing we do to ourselves is to "should" on ourselves constantly. We have all of these rules about how we "should" be and never leave room for just what is. Often we are completely unaware of the should. "I feel so upset over minor and material things" and I shouldn't. The problem isn't whether you care about material things or not. The issue is that you think you shouldn't feel how you feel.
When you remove the "and I shouldn't" from the statement then you just get to address what is happening. As soon as you introduce a "should" you are stuck. You will never find solutions and be able to make choices as long as you cling to the "should." If you just say "I feel upset" then you can choose what you would like to do to resource the feeling. If you continue to unconciously repeat that you "should only feel grateful and shouldn't be upset," you will only feel miserable and nothing can change. You have no choices in the "land of shoulds."
Gratitude is an important aspect to our lives. However, it will always be undermined by the "shoulds" and expectations we think are so important. When we are willing to just acknowledge what is - good or bad - then we may feel gratitude as well sadness, upset, happiness, fear, joy etc. The feelings aren't the problem. The judgment we put on the feeling is. Why is it bad to feel anger? Anger can simply be a signal that our boundaries have been crossed. Why is it bad to feel sad? We may have lost something and need to grieve. Why is it bad to feel ungrateful? This simply shows us where we may want to make some new choices or changes in our lives. When we allow our emotions, and don't stop them with "I shouldn't feel this way", they will naturally move through and we will be at a place where we have choices again.
So, what is? You like nice things. You like appliances that are efficient. The appliance you bought has some things that you don't really like. You didn't look at this appliance as closely as you would have liked to. Okay, what kinds of creative things can you come up with to resolve the issue? First, stop beating yourself up! Second, express your feelings of frustration through writing or drawing or tearing pages out of an old phone book. Next, come up with some things you have learned from this experience (without beating yourself up). Then, you are at a place to make some choices. You can do anything from buying another washer to just letting go and washing the cups by hand. You will be amazed at some of the creative solutions that can show up when you just address what is and stop buying in to the "I should/shouldn't have done this or that."