[DragonicRek]

Being personable In a jovial manner provides a positive vibe and most Importantly, a sense of connection between yourself and the representative which (as you've experienced), can make all the difference In a successful outcome.

Well done.

Making representatives laugh especially if they're in a better mood is always best. If you get a cranky rep and they don't want to lighten up it's really a pain.

Definitely.

Even a simple "I hope you're having a wonderful day so far", brightens the mood of the representative, hence provides a little extra boost In compliance with your request.

I agree. Another thing you can do is inflate their ego.
e.g. "I hope the might ___(company name) will be able to help me in this dire situation"
In most cases, the rep will respond with
"Of course, I'm happy to assist you. and I will help you to the best of my abilities"
That alone is a great boost to your se'ing odds