For the sentence: "I envy your seemingly convenient reason for X."
The "I envy" is genuine. The guy I was talking to makes trips. Let's say we both ride motorcycles, and I envied his seemingly convenient reason to travel to some place. I'd like one, but I need to work at finding places to ride my bike to. I didn't know whether he went to that place out of obligation or because he liked it. If the former, seems like it'd be in bad taste.