Being able to take constructive criticism is crucial for your growth as a human being.
At Toastmaster meetings, speakers are evaluated after they speak.
Being able to take feedback and suggestions for improvement are invaluable to your growing not only as a speaker, but also as a human being.
I have yet, in my infant career as a Toastmaster, to see someone being cruel to another when giving feedback.
Listen to what people say about you and if it's truly coming from a place of honesty and caring, figure out if listening to their suggestions will help you improve yourself.
A little positive feedback may feel negative simply because you don't want to be with flaws, but remember, nobody's perfect.
Just keep continuing make necessary positive changes and strive toward perfection and you'll get better each and every day.