Why don't I see some friend's updates on my Facebook home/newsfeed page?

I usually get the updates on every person usually engage with... but, for whatever reason, I have these two friends whose statuses updates or uploads/tagged pictures never appear in my home page... and I realize after I click ont heir names to because it says "2 new posts" with a blue circle in their profile picture on my friend's list... when I see their updates, it's been commented on/liked by other people and it's too late for me to like because it would be obvious for me that I'm stalking if I like something 5 days late...

Is there any way one can control who can get notified of your updates?