Nicknames can be hurtful, harmful…
Nicknames stick to people, and the most ridiculous are the most adhesive. Thomas Chandler Haliburton – Nova Scotian-Canadian-English politician and author.

Novelist Silviana Wood uses nicknames prodigiously in her writings.
Space limitations keep me from going on – there are many, many more of these.
* Certain behaviors also gave rise to nicknames. “El Tartamudo” was a chronic stutterer … an informant’s father spoke of a person nicknamed “La Bicicleta” because when he walked, he lifted his legs more than normal and of a woman nicknamed “Nueve Columnas” after a local newspaper with nine columns because she always seemed to know the goings-on before anyone else … another informant relates that a gossipy classmate was dubbed “La KTKT” (this was the teens’ favorite Tucson radio station in the 1950s-1960s) …
Nicknames can be hurtful. Nurse-teacher Marlene Ritchie says they can also be harmful. In “The Social Effects of Nicknames” (Child Research Net, January 22, 2010) Ritchie posits that a nickname reflects how others view the nicknamed person and can come to mirror how that person sees himself/herself. By their very nature, nicknames are exclusionary, Ritchie maintains, in that they separate people from the “in-group” (e.g., a cohort of classmates, circle of neighborhood pals, etc.).
That children can be cruel is pretty much an accepted truism. Some of the above nicknames – e.g., “Gordo/a” (fatso), “Tuerto”(lazy eye), “Sambo” (bowlegged) – are quite cruel. Were the children being intentionally cruel when they conferred these, and other similar nicknames, on their peers? Maybe (probably?) not.
I asked some nicknamed people who went on to lead what would be considered good, normal lives if their nicknames affected them negatively. One said she conditioned herself not to cry or be overtly emotional because the nickname that was thrust on her implied being stoic. The stutterer (“El Tartamudo”) didn’t like his nickname because, “I can’t control the stuttering – it just happens.” As a stutterer myself, I empathize with him. [It occurs to me that I escaped being nicknamed “El Tartamudo” because it was already taken.]