One of my favorite topics! I love my coffee. I have - on heavy days - 2 cups, 2x a day. I mostly make it at home, no fancy equipment except a nice quality percolator (part of the goodness is keeping it easy). Of course, I do dress it up a bit with flavors and whip cream. A good cup of fresh coffee is an incredible comfort to me.
Yes, it does have an effect. In the morning, it clears the cobwebs and helps me string a few lucid sentences together. In the afternoon, it reboots my circadian rythym, and gets me on my way for the remainder of the day.
I have trouble sleeping and have "tested" my afternoon caffeine as the culprit. I cut the p.m. coffee out for two weeks, wanting to see if it alleviated the dreaded catch-up-on-the-news-at-3-a.m. events that were wearing me out in the first place. It did not; I happily resumed my regular coffee regimen.
Then there was the era of pregnancy and breastfeeding. I recall that early in my first pregnancy, some study came out (to much fanfare) linking caffeine consumption to low birth weight. Seriously, my first pregnancy left me so DRAINED that my only hope of stringing two sentences together came in a Grande anything. This news was seriously disconcerting.
I actually sought out the specific study details (completely overlooked in the mass media) for hope. There it was: the study was made up of all these Swedish ladies who drank at least 8-10 cups of joe per day. And that's European-style coffee, certainly more potent than anything we buy here - even Starbucks (which I was addictd to). I could have two commercially prepped Grandes, and still be below that 50% threshold. Rationalize much?
Anyway, my research gave me the strength to ignore the stink-eye from patron and barista alike when I corrected their misguided assumptions that I should drink anything decaf.
I guess I can relate to smokers and drinkers in that I feel our culture is way too quick to deem anything enjoyable (requiring outside influences) as somehow being bad for you. My poor mom had cut so much out of her diet in the name of being healthy that she achieved a whopping 90 lbs. during a period of great stress. (A 75 year old woman needs better reserves than that!). Seriously, you can kill yourself trying to stay healthy.
Life is short. Enjoy what you can. Practice moderation.