I keep hearing that we should live in the moment. 

That I understand but disagree with, thinking that thought would be better phrased by replacing the word moment with “now”.

Moment refers to a very brief or specific point of time.

Now refers to the present time, and can be extended to a period of time.

Moment can be used metaphorically while now is more literal.

Now brings with it a sense of urgency and immediate action, while moment does not.

Wishes for a great day,

Each one a gift,

David/