Why is it so difficult to determine when a minor gift entertainment or incentive constitutes a bribe?

It is difficult to determine when a minor gift entertainment or incentive constitutes a bribe because there is no clear definition of what constitutes a bribe. Different countries and organizations have different laws and regulations regarding bribery, and the definition of a bribe can vary depending on the context. Additionally, the intent of the gift or incentive can be difficult to determine, as it may be given with the intention of influencing a decision or action, or simply as a gesture of goodwill.