Refuses to Commit
An immature man can't commit to anything. He can't make up his mind. He doesn't want to make decisions about things because he's afraid of being wrong or doesn't want to upset things the way they are. The immature man wants things to stay his way and doesn't want to make any large, life-altering decisions. He wants to stay free of anything that ties him down because he isn't ready to be serious.
Plays the Blame Game
Everyone in his life is at fault except him. This is a hallmark sign of an emotionally immature man -- one of the early warning signs, in fact. If he blames his ex-girlfriend, his mother or his boss for all of the problems in his life, it's probably best to run the other way. A mature man has a sense of his fault in things. He knows when to take responsibility for his mistakes and admits them.
He Has No Depth
If his life consists of PlayStation, delivery pizza and a dead-end job, you may have an immature man. Mature men have life goals and are actively working toward them. They have things they are interested in, things that make them tick. Men don't have to be as multifaceted as a character in a novel, but they should be invested in something in their lives. Immature men have no focus or direction. They have no aim or ambition.
Lack of Meaningful Relationships
Most guys have friends they drink with, but few have meaningful relationships. It's a red flag if a man doesn't have a meaningful friend or has never had a meaningful relationship in his past. It's a sign of immaturity if he's unable to form close bonds with people and be serious enough to have a deep friendship. The ability to form a close, serious relationship with another person is an essential sign of maturity in a healthy male.
He Can't Say "I Love You"
An immature man isn't in touch with his feelings. He can't express anger, sadness or love in any meaningful way. He may express feelings in inappropriate ways, such as teasing a girl he likes. A mature man is able to say how he's feeling and can express his thoughts to those who are important to him. The ability to recognize feelings and put those feelings into words is something that only an emotionally mature man is capable of doing.