Picking up unfinished games

After receiving my (late) Christmas present of Advanced Wars: Days of Ruin, I realised that I haven't even finished the fist one (AW:DS)!

This got me thinking... Why did I stop playing it? but better yet, why shouldn't I pick it back up again?

I'm now playing AW:DS and I will probably finish off, Burnout 3: Takedown (1 more gold medal needed!), Pokémon and some other games that I have effectively "shelved".

I just have to make sure that I don't distract myself from UNI studies too much :P