A critic can be one of two definitions, they are very diverse, and sadly interchanged too freely. The first meaning as shared by dictionaries is someone who expresses an unfavorable opinion of something and that something could also be a person. That also holds true for critical and criticism. Sadly that tends to be much more common than the second meaning of the word. The first definition is much more hurtful as it is usually personalized and many times with personifications.
The second meaning is much more respectful and is critical of 'a work' created / completed. The work is criticized. Yes, that may reflect on the creator of the work, yet the creator of the work has opportunity to learn from one who has more verifiable expertise. Their is some degree of knowledge presented with professionalism, even though at times austere. And, It is not personalized.
A simple rule I use to decide when which definition of a critic to use is when words like 'you, your, and [insert a name here]' is used, well the work is not being criticized, so it is the first definition. They are only expressing an opinion, it is unfavorable, expertise is unverifiable especially since it is of a person and not the work, and most likely unreliable.
If a critic offers a critical view (opinion or otherwise) of the work objectively with little subjectively then it is of the second definition. A bonding response of both having respect of the trade, craftsmanship, art, and etc. is established. A bonding with like interest occurs even to the extent of friendship, peer equality, and maybe teacher-student role undertaking, which could have reversal of roles through social interaction.
Then a choice of what the question above alludes is made by the recipient. It is not uncommon and matter of fact an innate response will occur with the first definition being a fight or flight response. The fight or flight response is just part of nature's programming within us. The outcome of those two responses offers worth presenting value. How instinctual a response contrasting a cognitive assessment and determined behavioral response could be 'how difficult one handles' the critic, especially of the first definition.
Criticism must have a critic. The critic is responsible for the criticism. They go hand in hand. Here again definitions come into to play sort to speak. How one plays is of question with regard to professionalism and social etiquette regarding criticism contrasting opinion.