It's special, because it has only one electron, while the ideal "noble gas" configuration (helium) would call for two.
Step-by-step explanation:
So in one way it could 'try' to gain an electron as any element from halogen group (F-Cl-Br...) would do.
On the other hand it could lose its one electron, in which case it would belong to the alkali metals (Li-Na-K...).
In practice, H mostly shares its electron, either by covalent bonds, or by donating an electron and working together with H2O to form the H3O+or 'acid' ion.
In short, H is too special to to put it in a specific Group.