When Do Games Become Too Big?

I'm currently playing Far Cry 4 which is a fantastic game and it's taking up a great deal of my free time. I received the game at Christmas along with a few others to add to my ever growing pile of 'to play' games. However, Far Cry 4 is that huge that my other games aren't getting any attention apart from the weekly high score challenges I participate in.

Ok, so I could take a break and play some others but once I start a game I now try and play it until it's complete as in the past I've taken a break from games and rarely or never returned to them.