What is the main long-term effect of high temperatures on computer components?

Generally, subjecting computer components to greater temperatures than they were optimally designed to withstand can ultimately result in permanent damage to certain parts of the machine. When one considers that much of the most important components are often made of wafer-thin components glued and soldered together, sometimes with electrical conducting paths less than a millimeter apart, it is easy to see why any kind of force that could warp the materials or "cook" them for extended periods of time could cause permanent damage to the computer.