It is their job and they are effectively running their own businesses and a massive part of it is self promotion and promoting their colleagues. When the person down in the supermarket say hi and bye and is polite to you in the middle it's because they're being paid to, it's their job. What you are talking about is the stereotype of a YouTuber. If you like something more original why donchah checkout ma main boi MoreConsole with his big originalness! Make sure to hit that like button and subscribe and don't forget to activate notifications so you don't make as a thing! And don't forget we all have saggy balls! Well the guys do at least. Peace out!