Some jobs are easier than others, even if they are pretty similar. Take for example working on the sales team of a company that has a monopoly in a certain product. Marketing in this case is rather easy as it involves maintaining the image of the company and persuading people that the company is really serving them the best they can.
On the other hand there are the really tricky marketing roles. For example, take Pepsi, basking forever in Coca-cola’s limelight. Now that’s a hard job. Or selling diet pills on the Internet, which is a really competitive market. Alternatively, try selling polaris suspension parts in a country that doesn’t really practice off-road racing. The secret is always to focus on your product’s strengths and making sure you understand the competitive environment you need to operate in.