The phrase "wishful thinking" refers to a type of optimistic or positive thinking that is based on hopes, desires and imaginations rather than facts or reality. It involves believing in something strongly despite lack of evidence or proof, often as a way to motivate oneself or others towards achieving a goal. The term can also be used negatively to describe unrealistic expectations or overly positive self-talk that is not grounded in reality and may lead to disappointment when the desired outcome does not materialize.