Forgive my silly title, and let me explain myself a little. First, a disclaimer: I've recently tried SWTOR for the first time and I've played until I reached level 21 (Scoundrel) purely as a F2P player. I liked the story experience and it kept me playing for a while.
Here's where I lost interest in the game, its F2P model, or rather how the F2P model was presented while I played. Now I'm normally perfectly fine with F2P games. If I enjoy the game, then I have no issues spending a fair amount of money into the cash shop or subscribing. It will most likely sound like a silly reason to most of SWTOR's players, but to me it's important enough to affect my overall enjoyment of the game : I felt punished when I played.
In most F2P MMOs, the optional subscription or cash shop items are sold as "enhancement" to your overall experience : "Subscribe and get 25% more XP and increased rare loot chances!", "Buy this item and you can alter the appearance of your character", "Buy this cool mount and make other players jealous!". These games don't really push a cash shop in your face, they'll make some mentions in loading screens and show a window at the start of the game showing specials in the cash shop, but short of pressing the Cash Shop button in the lower corner, that's the last you'll see of it.
In SWTOR however, while the items and subscriptions are also enhancement to your game experience, it's presented in such an outrageous way, in my opinion, that I couldn't help but be frustrated by it. "Good job completing this quest, here's your reward! Oh wait, you don't have your subscriber card? Well you can't have that item and that item, but you can take the rest.", "Traveling takes a while right? Well if you payed, you could learn to Sprint and ride a Speeder 10 levels sooner." , "Hey, you're level 20, you can ride a speeder now! Oh you're a F2P player? Well F2P players have to pay more for speeders", "Now that you're level 20, well you gain less EXP unless you subscribe", "Hey, you can do Space Missions now! Oh you did 3 missions already? Well you're done for the week since you're a F2P"
That last one was the last straw for me. Nevermind that I lost 2 missions trying to learn how to play (and survive...didn't work) these missions, after I finally succeeded on my 3rd mission I was blocked for the rest of the week, and that was it for me. I've never played a F2P game where I felt I was punished for not paying, let alone punished in so many areas. Not that I have anything against paying to play the game, I play both P2P and F2P and will gladly spend money in both if I enjoy the games, but SWTOR's punishment model doesn't make me want to pay to play or enhance my experience, it just made me want to stop playing, and I did.