I am not looking for work advice right now -

Well then, this isn't for you but for anyone else on the receiving end of vague criticisms. (Seriously, ref, don't read.)

Vague attacks are so destructive and they are everywhere that feedback lurks. Generally a vague attack is covering up something else -- maybe something unformulated. Maybe something a higher up mentioned in a totally separate conversation with the vague attacker. Even if the source of feedback seems well-intentioned, does anyone see a problem with responding like this:

"I completely trust that you can do any work we have upcoming . . I just don't think you're trying hard enough."

The trick is to not sound sarcastic, and say "What do you mean?"

or "When you say it doesn't look like I'm trying hard, do you mean that there was something I missed in my report or should it have been longer? Is that it?"

Following this response, I would hope for either a clarification or an opening to a different conversation.

Another possibility is this: "You're right. I seem to be doing well at this. Is there something more that you'd like me to do? Were you thinking of a promotion or transfer?"