Pretty well every culture on the planet uses stimulants of some sort, so I don't believe there is anything inherently wrong with caffeine.

In the past I used to get through the days at work with the help of multiple cups of coffee. But at some point I noticed that I was very speedy a lot of the time, so I stopped doing that. I run on overdrive most of the time as it is!

Now I usually only drink one cup of strong coffee in the morning. It wakes me up, as it is supposed to, physically and mentally. If I am very drowsy in the afternoon and can't take a nap, I will have a cup of coffee, or sometimes strong tea, although I found the former more effective. I very seldom drink caffeinated soft drinks. This pattern works for me.