I find costs for things in Jamaica a very similar to what we pay at home so for me I tip as I would at home. I too am in the service industry and tipping someone for a job well done is important to me. On the other hand if someone does a poor job or acts like an a**hole it will be reflected in the tip I give.

Funny story though, we were sitting in a local Jamaican establishment (won't name) and a worker brought me a beer which I paid for and I handed him a tip of one US dollar. He threw it back on the table and said "what am I going to do with one dollar!". I picked up my beer and my dollar and walked away.