I don't recall were I got this information, but about 20% of the population don't metabolize xanthines efficiently. I am in that camp.
If I have a cup of coffee at 7am I have VERY restless sleep that night and I can STILL feel the effects of caffeine the next day.
The irony is that I used to drink a lot of coffee. I even used to roast my own coffee beans. However I suffered from insomnia for years and I just refused to believe that a cup or two of morning of coffee were the culprit. One day I decided to give up coffee for a month. About a week in I started sleeping fine.
If I want caffeine now I'll have a mild cup of green tea...which is still very stimulating for me.
Caffeine is no joke for some of us.
Peace.
If your religion, faith, devotion, or self proclaimed spirituality is not directly leading to an increase in kindness, empathy, compassion and tolerance for others then you have been misled.