Do you think this is an okay meal?!
Do you think that will taste horrible?
Answers: Just Mash with Rocket?
Do you think that will taste horrible?
No; but you should not eat like that too often. You need nutrition!
It doesn't sound horrible so much as very boring and not very nutritious.
Potatoes are pretty useless from a nutritional standpoint. You would be better off sautéing a chicken breast in some butter and olive oil and eating that with the rocket. It will stop you feeling hungry for longer, assuming you are on a diet, and the only reason I can imagine someone eating mashed potato with rocket would be that he or she is on some stupid diet or other.
yes, it will be bad