Caffeine isn't heroin: tolerance plateaus after a few weeks of drinking coffee daily.

> nasty side-effects like heart racing and insomnia

I've been drinking coffee daily for two decades now and haven't ever experienced heart racing, nor insomnia if I limit my consumption to the A.M.

People do process caffeine wildly differently through. I apparently have genes that make me not very sensitive to caffeine at all, but I know this isn't true for everyone.