I'm writing on how coffee addiction is an act of bad faith and just looking for some input from others
He'd probably feel nauseous that people have a strong association with an inanimate object. It is impossible to say what he would have thought, and I'm sure he would have different opinions depending on how he was thinking at the time.
Sartre took opiates so he could stay up long hours and write. I think coffee would have been the least of his concerns; he probably drank six pots a day.
It would seem to me that because people are inconsistent - every time a coffee addict reaches for a cup of coffee they are making a choice. If they make that choice based upon "I would like a cup of coffee" then it is of their free will and choosing. If they say to themselves "I NEED (but not necessarily want) a cup of coffee" then they are removing themselves from their personal choice and acting in Bad Faith.
I saw sarte on a bathroom wall once, said something like To do is to be - Sarte To be is to do - Kant Do be do be doo - Cosby
It took it as referring to the general idea of bad faith, not bad religious faith. I can see how addiction could be viewed as bad faith, or at least having an element thereof, but I wonder why the OP focused especially on coffee...
Bad faith is the belief that that the negative is Bad because it is in the mind inescapable from logical thinking. What we put in the body in general is uncertainty of the momentary Senses. :mickey: