Many electronic products and projects fail for the simplest of reasons; Overheating due to inability to dissipate so much wasted energy!
Just as a marathon runner is limited by their capacity to perform under the stress of heat, so are electronic components. The amplifier and LCD TV in your home will need heatsinks to dissipate heat, for example. The next time you walk past your LCD TV, put your hand over the top to feel how much heat is coming from it.