The Clueless Guy is a very common motif in both shonen and shojo. Clueless Guys are very dense about the romantic or sexual interest of others. They are often naive and appear innocent. Although the Clueless Guy is closely related to the Pervert stereotype. Clueless guys have Pervert tendencies but try to hide or control them.
The Clueless Guy is a source for both comedy and story tension. They are razzed by both the more experienced cast, Perverts, and their love interest. They are usually completely unaware of the feelings a character has for him. Women often throw themselves (with the Clueless Guy inadvertently motor-boating in the process) at him to try to sledgehammer home their interest.
Basically the Clueless Guy is a prude (or a Pervert in prude’s clothing). It isn’t unusual for this stereotype to be the main character, or for the main character to have elements of this stereotype. Ichigo, from Bleach, has elements of the Clueless Guy.However, this stereotype is mostly found in harem anime and romantic comedies.
Other examples of Clueless Guys: Inuyasha, Renton Thurston, Edward Alric, and Tsukune Aono (from Rosario + Vampire)
The type is sometimes so socially inept that they make people suffering from Asperger’s syndrome look like social experts.
However, sometimes the Clueless Guy is a part of a character that is coming of age. Eventually the character matures enough that he can accept and acknowledge his own feelings along with the feelings of his love interest. Edward and Winry, Inuyasha and Kagome, Renton and Eureka are good examples.
In comedies, the Clueless Guy can develop into the Pervert.
This character type makes me groan. Sometimes it can be funny, but after seeing dozens of them, they were thin on the humor. Although I don’t mind this type when they are in a coming-of-age story. The development of the character makes the clueless stage endearing and helps the character show their development into emotional maturity more effectively.
It is a matter of how well the stereotype is handled. Cut and paste versions of it are tired.