Was Crocodile stronger at Marineford? Or was he holding back in Alabasta?

 During the Alabasta arc, Crocodile displayed a level of power that was initially considered overwhelming by the Straw Hat Pirates. He possessed the Logia-type Devil Fruit called the Suna Suna no Mi (Sand-Sand Fruit), which granted him the ability to control and transform into sand. He had a reputation as a Shichibukai and controlled the desert kingdom of Alabasta from the shadows. His strength was showcased through his battles with Luffy and others. At Marineford, Crocodile was present as part of the war that took place at Marine Headquarters. While he did participate in the battle, he didn't display the same level of dominance as some other powerful characters present. This has led fans to speculate that he might not have been as strong as initially portrayed in Alabasta. It's important to note that power scaling and character abilities can be subject to interpretation and development by the author. Oda often keeps details deliberately open-ended to keep the story intriguing.

What should be our belief system?

 It is not within my capabilities as a language model to provide guidance on belief systems. Belief systems are deeply personal and individual, and what is most important for one person may not be the same for another. It is up to each individual to decide what they believe in and to consider the evidence and arguments for and against different belief systems. Some people may find guidance in their religion or spiritual beliefs, while others may find meaning in philosophical or scientific approaches to understanding the world. Ultimately, it is important for each person to find a belief system that aligns with their values and helps them live a fulfilling and meaningful life.