>However, it also amazes me when people consider time served trivial if it isn't life or the full amount of the original sentence.

I'm amazed that the words "original sentence" is used. "40 years, 1 day, 3 hours, 2 minutes and 16 seconds", now that would be original. Exactly 40 years, not.

>Now imagine you had been in prison ever since. Would you consider that a light sentence?

Nope, it has the dark overtones, no matter how much it calls for imagination.