Naxar, 18%? That is too much!
Here in Toronto it is 15%, and if the party is more than six people, they automatically add the 15% on to the bill...
If service is good, I tip and I tip well...If service is bad, I still tip, but only add two pennies and nothing more...
As for Somali restaurants, if the server is a young person I tip them, if an older person - me don't bother...