Why don't the characters ever KISS already?

As you can see in the still from Raja Hindustani, sometimes the characters do. But it's rare. The censor board is notoriously unpredictable; no one wants to risk getting a rating that would scare away families. Also, Bollywood plays to a diverse range of people, from the illiterate and provincial to the worldly and urban. Ideas of morality differ widely from group to group. Why include a kiss when you can easily leave it out and avoid the risk of offending customers? Also, actresses don't want to lose their conservative fans, nor do they want to endure salacious flak from journalists. So they're not too keen on kissing on-screen, and many proudly trumpet their refusal to do it. 

You tug your ears in a variety of social situations, but mainly when apologizing, as a physical admission of wrong-doing and as a demonstration of repentance. Here Juhi, in One Two Ka Four, is about to let Shahhrukh out of the doghouse (how could she resist?)... 

Touching someone's feet is a sign of respect usually accorded to elders, or, as in this still from Kabhi Khushi Kabhi Gham, by (very traditional) wives to their husbands. Why is this considered respectful, you ask? Well, Hindu theology, and Indian culture in general, holds the feet to be the most polluted part of the body (the head, farthest away from the ground and least likely to come into contact with it, is the most pure). This is why you take off your shoes upon entering a temple (your shoes have been in constant contact with the ground), and also why you should never point the soles of your feet at someone (very rude!). Therefore making a point to touch someone's feet is a sign of your immense respect for them: you honor them so greatly that touching even their feet is a privilege. (Here, Amitabh stops Jaya from actually touching his feet, a common response -- indicating, perhaps, modesty? -- to this gesture of respect). 

You'll see in the films that, upon first meeting someone, a character will press his palms together and say "Namaste." You can equate this to a handshake if you'd like, but pressing your palms together connotes a respect the handshake no longer does (unless you consider the significance of refusing to shake hands, the gravest of all insults, which accordingly implies that a handshake does, indeed, show respect -- but enough, back to Bollywood!). For example, in this still from Raja Hindustani, Karisma is facetiously paying homage to Aamir, pressing her palms together and bowing to him subserviently.

In the song "Yeh Ladka Hai Allah" from Kabhi Kushi Kabhie Gham, Daijaan waves her hand over the bride's head and then, making a fist of her hand, presses her knuckles to her own head (cracking them). This action wards off the "evil eye" by symbolizing her willingness to take onto herself any evil that may target the bride. It's actually a way of expressing admiration for how lovely the bride looks (i.e., her beauty is so resplendent and her marriage is so auspicious that it's sure to excite jealousy and evil wishes).

What does it mean when you wear a bindi on your forehead?

Arguments have gone on for years, in classrooms and coffee houses alike, about the symbolism of the bindi. Some people claim it's the sign of marriage, though unmarried women wear bindis as well. Others claim its symbolism rests in its correspondence to an energy point, or "chakra," located between and slightly above the eyes. Everyone has a different opinion on bindis...but they sure are pretty, aren't they? At right, Kajol sings about her "bindiya's" words of wisdom in "Saajanji Ghar Aaye" from Kuch Kuch Hota Hai. Warning! Most bindis don't actually speak.

What does it mean when you wear red stuff in the part of your hair?

At left, behold Aishwarya in the role of Paro, wife of a rich Bengali aristocrat in Devdas. She's wearing a red dye called vermilion in the parting of her hair (enhanced a touch so you can see it clearly). This, unlike the bindi, has one clear meaning -- she is married, and her husband is alive. If she were to be widowed, she would cease to wear vermilion in her part. Legend has it that this ceremony began due to a slew of brides being kidnapped at the wedding ceremony. The groom would fight for his bride, and if he slayed the would-be abductor, he would smear his bride's part with the fallen man's blood. (It wasn't all the man's job, though: according to tradition, brides of the Kshatriya class should carry a knife at the wedding to help defend their virtue.) Hindi filmmakers love this: watch a few action movies and you're sure to see the hero smearing the villain's blood into his beloved's hair.

What does it mean when you wag your thumb at someone?

Making a fist and extending your thumb, as in the Western "thumbs-up!", then wagging it back and forth, is used as a "shame on you" gesture; also, occasionally, as a "nah nah" -- equivalent to the old "thumbing your nose" at someone, though that particular gesture fell out of fashion in the West a few centuries back. In this still from Devdas, Aishwarya is taunting Shahrukh, whose hapless character, Devdas, was unable to fasten a bracelet over her wrist, though she managed to do it in seconds flat. Nah-nah indeed! 

When someone looks especially beautiful, it's assumed that she'll attract a great deal of jealousy. Putting a dot of black on her face as a makeshift "blemish" serves to ward off the evil eye that might otherwise be attracted by her perfection. This is most often done to babies, but women occasionally place a black smudge on their faces when they're especially well dressed. Bharatanatyam dancers, for instance, will occasionally wear one during a performance. In the scene at left, during the song "Aankhiyon ki Gustakhiyan" in Hum Dil De Chuke Sanam, Aishwarya places a smidgen of kohl on Salman's lip as a compliment to his allure.

Usually this occurs in two different contexts in films: when greeting a guest, and when worshipping God. In the latter instance, a lamp, or a burning dish of clarified butter (ghee), is waved in circular motions around the image of a deity -- a ceremony called aarti. The person waving the tray is making an offering of the tray's contents to God. Oftentimes there are also sweets on the tray; after these sweets have been offered to God, they are given back to worshippers as sacred food, or "prasad." The tray is waved before human beings as a way of acknowledging the sacred within them; since guests are considered to be sacred, greeting them this way acknowledges their divine nature and conveys what an honor it is for them to visit. In the scene above from Kuch Kuch Hota Hai, Kajol honors her fiance thus because as her future husband, he is a form of God to her (at least until Shahrukh shows up).

In the still at left, from Dilwale Dulhaniya Le Jayenge, Kajol is scandalized: she's just asked Shahrukh's character what took him so long in that church they'd been visiting. He replies with a hand gesture that prompts her to shriek, "In the CHURCH?!?" Why is she so shocked? Well, in India, this version of the "hang loose" sign means that you have to go to the bathroom...or in this case, that you just have.