Principle of Privity of Contract, Kya Ho Raha Hai?

Arey, main toh 2 am ke aaspaas hoon, aur mere dimag mein ek hi sawal hai - principle of privity of contract, kya vo hamare dainik jeevan mein kaam karta hai? Main to socha, arre yaar, hum sabhi to shopping par jaate hain, restaurant mein khate hain, aur lekin humara contract saara waqt ek aur ki baat karta hai? Phir kya hua? Kya main to bahut confused ho gaya hoon? Privity of contract, yeh to aap sabhi jante hain ki yeh principle kis par aadharit hai, lekin kya yeh principle humare dainik jeevan mein kaam karta hai? Arey, please help!