I've been drinking caffeine since I came out of the womb. Doesn't have an effect on me anymore. I'll drink a monster and go straight to sleep. They're just delicious. Same with coffee.
So I'm not the only one..I drink coffee cuz I like it-I never can tell the caffeine.
Monsters and Red Bull put me to sleep. One of our EMS rooms has them and my partner knows if I drink one it's nap time.