When do you consider a Statement about here to be "rude" and not funny anymore. Let's say she studies math:

Statement 1: "You? You never study math. You wanna tell me you are that smart?" (with a smile of course)"

Statement 2: "Math? You will never do it you are gonna quit" (also with a smile)

Would you consider the second statement as rude? How do you set a boundry?