Have a good meal.

Well, that depends on the circumstances under which you said it.

You say "eat well" to your friends (the subtext is don't wronged yourself), and you say "eat well".

At the dinner table, greeting guests is enjoyment! Or have a good apitite (look it up yourself, which means appetite)

If you want to say angrily (ironically, it can be understood as enjoying your meal, cooking very little, this is very funny, and I will attack entertainment when I write), you can say: shut up, U bastard, U rotten ... and so on.

I'm explaining what the third one means: shut up, you're an asshole (that is, you're a bad person) and you suck.

Isn't that interesting?