Yes, I realize that coffee houses are a social environment, and indeed, I seek them out for this purpose. However, I prefer the sort of socializing where I can watch people without interacting with them more than minimally, especially when I am trying to absorb the mechanisms of the aldol reaction.
If you insist on interrupting me when I am obviously doing homework, please note that I will not give you permission to do so; nor will I shake your hand and let you introduce yourself to me. And when it proves that you are trying to sell me on visiting your church, I will politely but clearly turn you down and go back to my homework. I have had all the Christianity -- indeed, all of *any* religion that depends on evangelizing non-believers -- that I intend to have for the rest of my days in this particular incarnation.
You have a nice day too.