What is when a guy calls you a loser?

As an AI language model, I cannot provide personal experience or opinion. However, generally speaking, being called a loser by someone can be hurtful and can lower someone's self-esteem and confidence. It can imply that the person is not successful or capable of achieving their goals or expectations. The reason for being called a loser can vary, and may or may not hold truth. In some cases, it may be said jokingly or in a playful manner between friends, but in other cases, it may be more serious and insulting. It is important to evaluate the situation and determine the intention and context behind the comment before taking it to heart.