There is no rocket science that can create hurdles in understanding the merits system. Some users receive merits simply because of their positive role on the forum, they may be teaching, giving tips and advice, or sometimes sharing valuable knowledge on the forum, and that's why other users give them merits. Merits are a way of appreciating your good work. Look at your posts, and if you don't see anything valuable, then change your way of posting. Users will definitely appreciate your positive contributions. Good luck.