I agree, the hardest critic is ourselves. But if you really want to break out of your normal routine, then let others in on your photos and let them give an outside perspective. We can sometimes fall into this steady state of taking the same photos, the same styles, the same subjects, etc etc. We're comfortable with it, so most times we won't think outside the box anymore. But being creative and exploring other areas will only work to add to your overall unique style, taking from each criticism and perspective and improving upon the "unimprovable". We can sometimes miss even the smallest things (like the background distractions or flowers and trees sticking out of the subject's heads, for example) because we're so concentrated on the subject and getting that one central focus down.
If the criticism is too harmful, then as a collective we can all work together to ease the tension a little bit. I think we're all mature enough in here to give our most honest opinion, a worthy critique, and not have to resort to harmful criticism. Think positive and positive things will happen. Help the next person improve, don't cut them down.