These words and phrases quite obviously have different meaning.
If you can direct us all to the dictionary or phrasebook where 'disappointment' and 'frustrating' are described as meaning 'very good' then I might understand why you're so fundamentally misinformed as to how words work.
Your assessment is principally a negative viewpoint, mine is an entirely contrary one to that.
Your assessment remains one I disagree with. Try to follow the premise.