If you’re reasonable, nice, and persistent – in other words, if you’re easy to help and easier to help than not help – you’re going to do well complaining in almost any circumstance whether it’s the cable company, an airline, or the DMV.
A bureaucrat may go out of their way because they sympathize with you or at least because you’re nice, nicer than most of the people they deal with. A hotel may offer you compensation because they genuinely feel they’ve shortchanged you in some way, or because it’s cheap to make you feel better about your experience. An airline’s rules are so complex you might get what you want just by finding someone who doesn’t search the rulebook for a reason not to give it to you (call center roulette).