What term best fits the idea of making decisions based on inflated expectations or unproven assumptions?

The term that best fits the idea of making decisions based on inflated expectations or unproven assumptions is "Wishful Thinking." This concept refers to the tendency to believe in the possibility of a desired outcome, regardless of evidence or rationality. In essence, it involves forming expectations that are overly optimistic and not grounded in reality, which leads individuals to make decisions based on what they wish to be true rather than what is supported by facts.

The other options do not adequately capture the essence of this concept. For instance, "Inconceivability" refers to something that cannot be imagined or comprehended, which is a different notion altogether. "Not Drawing the Line" pertains to ethical boundaries and the failure to set limits, so it is not focused on expectation or assumption. "Tabloid Thinking" typically involves sensationalism and a lack of critical thought, but it does not directly connect to making decisions based on inflated expectations. Therefore, "Wishful Thinking" is the correct term that aligns with the concept described in the question.