Frankly, if you're NOT playing Enemy Within while drinking tea then you're playing it wrong. This is a game that lets you save the planet by introducing rubbery alien invaders to sizzling, laser-death one turn at a time. It's immensely polite in that way.
So, take your turn. Move your troops around, make your shots, go into Overwatch: whatever. Now, sit back, sip some delicious beverage, and watch as your foe attempts to respond. Ah, cunning move, Mr Thin Man. It's basically chess for people who don't wear blazers, have allergies, or call themselves Tarquin. And the best bit? Every level is still as tense and exciting as your average session of Battlefield or COD, because the game is so smart and balanced. Tea and tension? Yes, please.