Reasons for not finishing Moby Dick are easy to find: It's too long. The story wanders around too much. I didn't know what he was getting at most of the time. There's way too much detail about whaling. Killing whales is cruel and immoral..
Reasons for wanting to finish the novel may seem vague, but here are some: It is recognized as an American epic. I want to know why references to Moby show up in movies, songs, art, and talk shows. I have tried to finish that novel 2 (3, 4) times, but failed each time. I don't like failure. I want bragging rights.
If you are here, you are wanting to either begin or begin again reading Moby Dick, and you are looking for some help.
If you are looking for a study guide like Spark Notes that summarizes the novel and gives you answers to class test questions, this is not the place to be. This site targets those who want to read Moby Dick from beginning to end.
Early in the novel, two categories of people are identified: land people and sea people. Land people demand security, parameters, and answers. Sea people know that all three of those conditions are at best, relative, at worst, nonexistent.
When you sign on and board the ship, be Ishmael. You must become a sea person, like it or not, for three years.
Some days will be challenging and exciting. Most days will be tedious, but that tedium is fertile soil for wonder, thought, and, ultimately, realization.
Survive this journey. Go with the flow. Accept what is. Read page after page after page.