chai-pani
You do nota have to give any tip money to anyone during entire process.
But if you can give couple of bucks (or quids or euros) to hotel bell boys, car service drivers in LA/NY/Chicago/London, why not do the same in India.
Why should the poor guy (who is neither unemployed nor a criminal) have to even mention chai-pani or baxis or anything?
I carry a bundle of INR50 and INR20 and give away wherever I get manual service (20, 50 or 100 depending on service provided - with nothing for poor service).
I try to make sure that I do not give tips for any rule breaking. (like trying to give someome INR to put you in front of the queue or something like that)