public interface ISomeUsefulName
{
    IList<User> FetchUsers();
    User FetchUser(int userId);
    bool SaveUser(User user);
    bool DeleteUser(int userId);
}

public interface IRepository<TYPE, KEY>{
  IList<TYPE> GetAll(KEY key);
  TYPE GetById(KEY key);
  void Save(TYPE obj);
  void Update(TYPE obj);
  void Delete(Key key);
}

public interface IUserRepository : IRepository<User, int>
{
   IList<User> GetAllMyFavorites(ICriteria crit);
   IList<Events> GetHistoryByUser(User user);
}

public UserController {
  private _userRepository = null;
  private _eventsRepository = null;

  public UserController(IUserRepository userRepository,
  IRepository<Events,int> eventsRepository)
  // if you are doing here just CRUD use the generic signature
  {
    _userRepository = userRepository;
    _eventsRepository = eventsRepository;
  }

  public MarkItAsGoldPartener(int userId){
     var user = userRepository.GetById(userId);
     user.PartnerType = PartnerTypes.Gold;
     userRepository.Save(user); // the user in member name is useless
     eventsRepository.Save(new Event(){Message = "The user" + UserId + "is golden" });
  }
}

public interface IUserList
{
    IList<User> FetchUsers();
}

public interface IUser
{
   User FetchUser(int userId);
}

public interface IUserStore
{
    bool SaveUser(User user);
    bool DeleteUser(int userId);
}

ICrud<T> { }

IStore<T> { }