Good manners in coffee shops are crucial folks. Otherwise you could end up being savagely dealt with like these poor unsuspecting folks. 

Khalil Sehnaoui's recent visit to a coffee shop was ruined thanks to some noisy neighbours who were 'loud and rude' during what sounds like a business meeting of some description. 

Rather than whine on Twitter about it., Sehnaoui exacted a brutal revenge on them.......before taking to Twitter to brag about it. 

Let it be a lesson to us all. Don't talk about your 'perfect' ideas in public.