No it’s not choosing the occupation that pays the most for the least amount of effort. It is about choosing an occupation that does not harm other beings. This means not being involved in the weapons trade, neither designing, making or selling of weapons. Not engaging in slavery, prostitution or any other form of buying or selling children or adults. Not to be in the business of providing meat or flesh taken from animals. Not to be in the business of selling products of intoxication, such as alcohol or illegal drugs. Also not to be involved in products that are poisonous or harmful to the environment. This means that if the product you make is safe for humans, but causes the death of other beings, it is not correct.