The experience starts with a card.  You've played magic before, you know the rules, and you know how you like to play.  And this card is perfect!  For... something...  Oh Yeah!  Card #2!

Those cards might come from a pile, or maybe you're trolling gatherer.com at work, but the result is always the same for me: total immersion.  There's a universe of thousands of cards waiting to be exploited and only 60 spots in your deck.  Can you find a combination to deal with 4 lightning bolt 4 shock?  What about 4 mana leak 4 rewind?  Some decks kill on turn 2.  Some use alternate win conditions.  Some decks have a swarm of small creatures.  Some decks have none.  The possibilities are endless.  And the inter-relationships between cards are such that no deck can ever be truly dominant and every card has a counter.

And no deck wins every time because sometimes you just get a shit draw.  That's life.  The pacing of the game itself (since deck building is really only a meta-game) is superb.  On turn 1, people tend to do things designed to be done on turn 1.  Their power grows somewhat linearly from there:  perhaps getting a 2 drop on the second and if they're lucky a 3 drop on 3, but rarely does it play out perfectly.  The deck might be designed to kill on turn 3, but a bad draw or 3 can have you waiting on that one card you need for 10 turns until it's much too late.