Does the phrase "should have" imply a sense of regret? Then does the phrase itself includes a negative nuance?

Rebecca

Yes, you're absolutely right. "Should have" is often an expression used when you are regretting something, or discussing something in hindsight. It doesn't necessary have negative connotations each time, it depends on the context and idea being expressed. Ex: I should have gotten up earlier. Then I wouldn't have been late to work. Ex: You should have made an appointment. Now you will have to wait for an hour.