How much of a derogatory or insulting element is there in calling someone "ha'er" in Chengdu?

Yes, it means fool. Stupid--Silly--Ha'er is the Sichuan dialect. As time goes by, everyone uses Ha'er. Generally no one uses the Sichuan dialect for Stupid.

It depends on who is talking about you. If you are a good friend, classmate or colleague, you can say this word at any time. It has a sense of randomness. In QQ chat, I feel that I am talking to my classmates. Frequently using "ha" means "silly".

If people with average connections, even classmates, friends and colleagues say this word, they are definitely scolding you and displeased with you.

Generally, Sichuan people like to scold others like this when they have conflicts with strangers. For example, conflicts on a bus that are too crowded, or being blocked while riding a scooter are not big things, but they are very unpleasant when they happen. , and often blurt out the sentence "You are so stupid".