Tipping the dealer on big wins is not only a nice way to treat the dealer, but it's good karma for this gambler. It may help even more when it comes to getting rated. Not all dealers and pit bosses seem to have the camaraderie as noted above, but many do discuss players at the table and the pit bosses control your rating.
This isn't to say that a pit boss will say your play is less than what it is, but not tipping or treating the staff nicely won't help. It's always a good bet in life to treat others the way you want to be treated and the same thing can be said in the casino. Being nice to a dealer is not only good to make the world a better place (insert ethereal music here), but it can also help your players club account.
We're usually chummy with the dealer since we have face-to-face access. But, when playing 1st or 3rd base (either end of a table), we have easy access to the pit boss and tend to be chummy with the pit boss. It not only makes our time gambling more fun, but we firmly believe the positivity helps create good karma for the table.
The odds are against us in all casino games so if we don't think positive then who will?!