"The way caffeine affects you varies from person to person" absolute facts.
If you ever sign up for something like 23andme they have all types of genetic indicators to measure: one being whether you're likely to be affected by caffeine or not.
People think it's insane that I can drink a 20oz of Red Bull and knock out 10 minutes later. Caffeine really don't hit me like that. I've literally pounded 3 of those 20 oz's back to back to back and was barely phased. I probably could've done 2 more. Easy work.