people say every habit has got some disadvantages also.....has reading also

Reading fictional novels may have a disadvantage in that you may tend to fantasise and live in an unreal world. Most novels are inspired from real stories, but there are always unreal elements introduced by the author to give it a dream-like quality. If you read too many fictional novels, you might just get a false idea of life, if you are easily influenced.

Eyestrain. They can take the cent for this one, it's too easy.