I never used to be much of a coffee drinker because I had never had great coffee.
Last year I went to a cafe which served coffee that was so strong I could not finish it yet it did not make me anxious or jittery and it kept me awake for a long time into the afternoon despite lack of sleep, since then it has become my coffee/cafe of choice by a long shot and the slightly bitter taste has grown on me.

Different coffees effect me differently, I soon learnt it is down to the bean not the brewing process, some coffee will make me very anxious and panicky(anxiety disorder, I guess you could say I am a coffee snob by force not by will :)), while other coffees despite a double shot, and seemingly a lot of caffeine will not keep me awake for a bender and I could just go to sleep.

I remember reading once that coffee contains other stimulants besides caffeine, I dont know if this is true or not but it would sure explain things.
What are peoples thoughts or knowledge on this?