Feedback is a good thing.

If you pet, you get a message about N of 10 done.

If you're past 10, you get a message about having to wait.

BUT if you pet the same meeroo again, and it's outside the 4-hour limit BUT you've not yet petted 10, you get NO feedback.

The was baffling until I realized it was because all three conditions must be met for your interaction to get NO feedback. Now that I know what it is, I know "no response" means you've already petted that Meeroo, not yet petted 10, AND it's past 4 hours since you last petted.

Of course, "no response" could also mean a problem with the HUD, the Meeroo, the sim, ... so perhaps it would be wise on the next update to add a response message?