Under Indian Contract Act

What if your neighbour ordered a pizza, but it was delivered to you by mistake, and you galloped it, are you bound to pay him? What if you are standing on the roadside and auto-rickshaw comes beside you and the driver asks, do you want to go sector 22 and you sit in the rickshaw, without contemplating about the fare, are you bound to pay? Yes, you are bound to pay in both conditions you can’t make excuses that there was no contract.