Hebrews 10:31

Ok, so Starbucks is easy to take on - they sell overpriced beverages marketed as an item of convenience and status. If you attack their appearance, they will be forced to withdraw to finance their marketing and brand reinforcement campaigns. Send the smelliest of your minions to Starbucks, and ensure that they loiter while displaying their drinks in public places. Give empty Starbucks cups to the homeless. I will be able to conduct the pyromantic rituals to determine your success rate in around seven hours.

Tim Hortons is a cultural icon with near universal appeal. I suggest engaging them diplomatically.