I thought he is right in that coffee only provides an up when you are not used to it. Once you are, you need it to hit your normal baseline. So still an up, but not a net gain anymore.

Is that not true?

As a person who had to hit 2L/day to be able to work at some point in my life, I can definitely can say that coffee tolerance and addiction is real.

The only good part is it resets in ~10 days.

That depends on how you metabolise it, which can be very different. (genetic variation of neuro-receptors, liver, whatever) For most people about a week of abstinence would do, for me it needs two. Call it 'caffeeine fasting'.

Similar with nicotine btw.(especially sense of smell!)

I think there is a strong point for you to break down your stance, if you want to be heard.

It's not like people would believe you but not someone else just because you say so; you both are strangers to me, so only facts matter really.