Greetings
In Kenya, every interaction begins with a greeting. Even when you walk into a store, you shake hands and make polite small talk with the proprietor. Shaking hands upon meeting and leaving is customary among all the men present. Women shake hands with each other, but only in more formal settings. Young men prefer soul-brother handshakes and other finger-clicking variations, whereas a common, very respectful handshake involves clutching your right arm with your left hand as you shake or, in Muslim areas, touching your left hand to your chest when shaking hands.
Greeting exchanges typically last a minute or two and are often performed in a formal manner between two men, particularly in rural areas. Long greetings aid future negotiations. You can say something like "How are you?" in English or Swahili. "All right, how's it going?" "All right, how's business?" "How is the family?" "Fine, thank God." When someone is speaking to you for an extended period of time, it is customary to grunt in agreement or say thank you at regular intervals. More greetings are exchanged during conversation breaks.
Hissing ("Tsss!") is a common way to draw the attention of a stranger, though it is less common in more sophisticated urban settings. You might get a fair amount of it yourself, and it's perfectly acceptable to hiss at a waiter in a restaurant: it won't offend anyone. Avoid yes/no questions because answering anything in the negative is often considered impolite. When making inquiries, avoid phrasing them in the negative ("Isn't the bus leaving?") because the answer is frequently "Yes" (it isn't leaving).