Use 'meh' to show you don't have a strong opinion on something.

Indifference Expressed

'Meh' can also be used as a non-verbal gesture, like a shrug.

Non-Verbal Usage

'Meh' often fills in spaces in casual conversation where a detailed response isn't needed.

Conversational Filler

'Meh' as an adjective describes something unimpressive but not terrible, just lackluster.

Expressing Mediocrity

Using 'meh' conveys a lack of enthusiasm but isn't harsh like outright negativity.

Neutral Sentiment

Never use 'meh' to describe something you are actually fond of; it implies the opposite.

Not Suitable for Praise

 which was only four months removed from my sort of "meh" town hall. We were out of money at this point, and I was terrified. But we made a couple of decisions that seemed to have long-term importance for our efforts.

James Rhee: The value of...

 I want to know with this mechanical problem is a science fiction problem or a real-life, real mechanical problem? Bona fide mechanical problem. Real or not, is that right? Do we go bing or meh? Yes.