I haven't been able to properly cry in a few years now. Even when I'm really emotionally moved in private, I manage a couple of tears at most. Possibly because I numbed myself to the point that showing much emotion at all is difficult, be it anger, happiness, sadness, whatever.
It does mean I have less to bottle up inside of me though, seeing as things don't really affect me much. It takes a hell of alot to get me angry.
I actually hate it, as a result getting close to people is near impossible seeing as I can't show any affection to people or even seem like I care, even when I do.
I don't believe it stemmed from any "showing emotion is weak" thoughts, more along the lines of "feeling sad/worthless/depressed all the time sucks, lets drink the pain away untill you can't feel anymore". Yeah, I'm an emotionally healthy human being.