Wow! I guess I had it all wrong!
Two instances come to mind that actually involve air travel. In the first, I approached the gate agent to inquire if there were any upgrades available. Unfortunately, my ticket designation did not allow for upgrades. Okay. Thank you, anyway. I should add that my demeanor was polite, friendly and confident. He called me to the desk after they had started the boarding process and I got the upgrade.
In the second instance, I asked the agent at the ticket counter if there were any upgrades available. There weren't. Okay. Thank you, anyway. Again, my demeanor was polite, friendly and confident. We chatted a little...very light-hearted somewhat joking around and he "upgraded" me as much as he could. He put me in a window seat behind the exit row where there was no seat in front of me.
I have found in most cases (even those that don't involve air travel) being polite, friendly and confident AND willing to accept "No." for an answer seems to work very well. I'm not saying I always get what I want, but I'm surprised at how frequently people do want to do nice things for others.