Used when one is happy,
sad, excited,
etc.
Usually used when one is irritated, however.
It is becoming quite a
common occurance in the vocabulary of Western Pennsylvanian school students.
Student 1: "You're such a bitch, Haley."
Student 2: "MEH, Caitrin. Mehhhhh."
or
Boyfriend: "Melissa, this
just isn't working out."
Girlfriend: "But..But...MEHHH]="