I'm always hearing comments like,<span style="font-style: italic"> "once you go synthetic, you'll never go back."</span> Why? What am I missing? And then I'll read reviews on Amazon about Royal Purple and people will say things like,<span style="font-style: italic"> "my engine feels more lively now; the engine revs up quicker."</span> Does full synthetic really make that much of a difference in the way the engine runs? Because if it does, that would be a good reason for buying it. But if it doesn't and you're a guy like me who enjoys sliding under the car twice a year, then that would mean I'd have to cut back to once a year with synthetic and the thought of that is disheartening. I cherish my under-car time.