Quran 50:16 states that Allah is closer to man than his jugular vein and Quran 2:115 states that wherever you turn, there is the Face of Allah.
Now to answer why He cares, the Quran states that He specifically created mankind to know Him.
And indeed, the recurring injunction in the Quran is to remember Allah, because you already know Him—Quran 7:172 states that we testified to His Lordship in a pre-birth state.