"Don't interrupt me" my mum used to say when I was getting told off. As humans we see it rude to interrupt people. However computers do not the same hang ups. In fact a essential part of how a PC works is the ability to interrupt the current flow of logic. There are different kinds of interrupts, each work in different ways and are handled in different ways.

An interrupt is a signal which is sent by a hardware device or by software to inform the CPU that something has happened. The CPU then must deal with the interrupt before continuing with it's current flow of logic.

Interupts in practice
Buffers and interrupts
Interrupt priority
I/O Interrupts