I have difficulty accessing and expressing my emotions, particularly showing that I am sad. This is probably due to having been raised by a mentally ill mother who would shame, mock, or even punish me if I cried. (I've heard that boys are abused in that way: shamed and mocked for crying, but I'm a girl, so go figure. In our household, Mother was the only person allowed to express anger, hurt, sadness or other negative feelings, the rest of us, including Dad, were just supposed to be happy and grateful all the time.)
So sometimes when I am really down, and feel a NEED to cry, I can't! Its very uncomfortable, that "blocked" feeling.
Sometimes I can reach that point where I am able to cry if I listen to very sad music, and its almost always very cathartic; I feel a sense of relief after a good cry.
But if sad music doesn't do the trick, then I use alcohol; becoming slightly intoxicated will disinhibit whatever part of my brain is damming the tears, and I can burst into deep, wracking, cleansing sobs, but I prefer music. No calories.