Yes, data mining can be a little difficult in job sites because of the complex data sets given to analyze and the techniques and algorithms can get confusing sometimes. But, if you have the right skills, it is easy to deal with. Having patience while cleaning and preprocessing before analysis is the key. Learning the machine learning techniques and programming beforehand can be of great help too. Anyways, the difficulty level comes from various reasons like complexity, expertise, and more. The right skills, techniques, and tools can help in discovering insights and patterns with ease.