I think that for every person it is quiet useful to admire someone. But I do not mean when you like the way someone is dressed or looks. Actually I think that it is important to preserve one’s personality in everything. I mean that it is very good to look up to someone who possesses some positive qualities or has done something good and worthy. To my mind young people especially need such heroes. Mostly people find idols in such spheres as music and cinema. Why do we need such examples in life? Generally speaking we need such idols to achieve something this person has already achieved. The most difficult thing here is to see in your idol not only good points, but also bad ones. Well, some people deliberately search for bad sides and admire them. For example, Jim Morrison died many years ago but still remains one of the most popular rock stars in the world. It is no secret that he was a drug addict and liked alcohol. All these «hobbies» influenced his life (and death) greatly. And even now most of his fans think that drugs and alcohol help them to be closer to their "god". Maybe they just see no evil in all this.
The other problem is that very often people do not understand that celebrities have private and public lives. It is important to remember that public life for celebrities is an essential part of their profession. And lots of the things they say or do are just a part of their images. If you really want to learn something good from your idol, then you need to seek information of non-public kind in reliable sources. Maybe you will find out something good for what you can really respect this person.
To my mind it is better to admire not someone’s appearance or popularity, but someone’s professionalism. There are lots of examples when people become very good actors, musicians, sportsmen, engineers…etc., only because their idols were professionals. It is great when your admiration for someone helps find one’s way in life.