It sounds like you're a mature designer capable of taking criticism without any issue whatsoever. Most designers aren't like that, and unfortunately many who are can be difficult to work with because they think everyone handles criticism as "well" as they do.
That said, some people try too hard "not to be a dick", and while nice and polite, they end up supplying watered down, fence-sitting, egg-shell treading fluff instead of useful down-to-earth efficient feedback.
Some designers get emotional. That's good - but they need to learn to channel that emotion into reasoning and solid foundation arguments to support why they did what they did. If they can't do that, they need to work with people who can assist them in doing that.
A colleague once used "intuition" as her rationale for a design/IA decision that was going to negatively impact on technical work I had to do. My criticism was harsh in reply, and I'm sure she thought I was "a dick". Well, that's just tough. Build a bridge and let's move on to the next task. All intuitive decisions can be unscrambled or decoded to find their basis. Especially true in design environments where you're working within defined limitations, scope and objectives. If you can't find a basis, then unload the criticism, keep our humor, and let's solve the problem rather than mess around.
I already know the benefits of my design, that's why I presented it. I don't need you to point them out again. I need you to criticize my design and think hard about edge cases I've missed. Don't waste time trying to think of something nice to say, spend your time trying to tear my design apart.
I might feel bad to have the flaws pointed out, but I'll feel a hell of a lot worse if we go forward with my design only to find a devastating roadblock months down the road.