s'attendre à

Question

I feel like I will never get this. You wrote "Note that s'attendre à is usually used for negative expectations (i.e., I expect something bad)" but then "You're expecting some happy news" is "Tu t'attends à de bonnes nouvelles." Happy news is neither negative or bad.

Answer

It is very tricky.
Why not try to think of s'attendre à as "to forecast" or "to predict" or "to foresee"?
This may help you to understand "Tu t'attends à de bonnes nouvelles" in the sense of foreseeing some good news, which is not a negative feeling,  but one of exciting expectation.
The lesson states that s'attendre à is "usually negative" therefore implying not always.