in Doha, u can try give some tip to grocery's delivery guy any amount, forget %, forget couture all that thing just look into their eyes how happy they are even 1reyal tip from u. pretending u r him at that moment. feel the heat & exhausted from him. I’m sure next order he will come with smile or even quicker. in Thailand no tip is ok but look very bad if u do not. u don’t have to tip everyone, everywhere you go. just be happy to give that’s all.