It really depends. I don't get particularily annoyed when people ask for subscribers. I usually just go on to a new video right at the end, before the whole "Like us on Twitter and Facebook and be sure to subscribe" part. That being said, if they constantly ask for subscriptions or likes, I will get annoyed. I'm not talking about a short "Like and subscribe" pitch at the end if a video, because those are easy to ignore. I am talking about someone who always has a popup asking for likes.