Just happened to go to McDonald’s after a long time(there’s no McD in Goa and I sort of prefer KFC nowadays)
What caught my attention was this new ploy by McD( cant call it a scheme as it isn’t really available). Here’s the thing:
Right next to each counter are placed a couple of sandglasses .as soon as you’re  done ordering the assistant flips over a glass. If your order isn’t ready in 1 minute (the time of the sand glass ) you get a complimentary small Coke.
Why this rocks?

• It gives you something to do while waiting by turning the whole drab affair into a small race against time
• It probably motivates their employees to turn out orders faster.
• Most importantly,it encourages BUYING another burger.How? because people just love seeing things in pairs :  Socks & Shoes   Fish n Chips  Crime & Punishment
  … and guess what else .. Burger and Coke
  A single unpaired coke on a plate may just not feel right and can nudge u into buying another burger.
  Here’s the fun part: even the cheapest burger is costlier than a small coke, say the coke costs $20 and the cheapest burger is $40 . They need half (conversion rate : 50%)of the people to act on their impulse.If a person already bought a big meal, he may not mind spending a little more.Also, since there are costlier burgers, the conversion rate isn’t that harsh.