Criticism is the best motivation.

If you are motivated to BETTER yourself, the form in which you are criticized is not a problem. Get value out of any formulation, as long as it's worth it. Where and how criticism can be useful? If your are criticized by your colleague, an expert in the field you're talking about, listen carefully. Even if she or he expresses her/himself harshly, the content may be really important. Perhaps, arguing critically and constructively, he can show you the right direction, help you look at the question from another point of view or just share fresh thoughts and ideas. And that's exactly what you need right now!