I’m one of the 10% of Americans who are NOT addicted to caffeine; this has some distinct pros and cons.
pros: 1) I can start my day w/o being a complete bear in the morning until I’ve had my coffee (okay, that one’s not entirely true: sometimes I’m still a complete bear in the morning but it’s not due to short-term caffeine withdrawal, it’s due to the fact that mornings just start too dang early ;\ lol), and 2) because I’m not inured to its effects, caffeine is actually quite effective for me when used for medicinal purposes, like headache relief.
this leads me directly to the cons: 1) since my body does respond quickly and strongly to caffeine as a drug, I need much less than is included in most OTC aspirin+caffeine combo remedies, and 2) when I take the recommended dosage of medications that include caffeine (the amount of which is probably intended to take into account most people’s high tolerance for caffeine), I end up WAY jittery. not fun.
note to self: take HALF of an aspirin+caffeine combo tablet, then take one non-caffeinated ibuprofen tab to augment.