What people seem to forget is that immigration needs to make a decision about visitors to their country in just a few minutes. And they don't know you, they ca

What people seem to forget is that immigration needs to make a decision about visitors to their country in just a few minutes. And they don't know you, they can only base it on what you tell them. Certain things will raise red flags and nobody in immigration got fired for denying someone entry. For example Singapore has a problem with young girls from SE Asia entering Singapore to be sex workers (lots more money). So if you're a young, single woman coming to Singapore and don't have a good story as to why, they'll immediately assume you're at risk for overstaying and/or working illegally.