Importance of parallelism

From a programmer's perspective, it would have been very convenient if the computer hardware of today had been a 100 GHz single core CPU rather than a three gigahertz multi-core CPU, and we wouldn't need to care about parallelism. But, as the evolution of computer hardware is going in the direction of multi-core CPUs, programmers have to use efficient parallel patterns in order to make the most out of the hardware.