Steam – return a game I activated through Steam and bought from GameFly, and get a refund if I have never downloaded it to the PC

This policy has just changed.

Now it's possible to ask for a refund within 14 days of purchase, provided you have played it for less than two hours.

You can request a refund for nearly any purchase on Steam—for any reason. Maybe your PC doesn't meet the hardware requirements; maybe you bought a game by mistake; maybe you played the title for an hour and just didn't like it.

It doesn't matter. Valve will, upon request via help.steampowered.com, issue a refund for any reason, if the request is made within fourteen days of purchase, and the title has been played for less than two hours. There are more details below, but even if you fall outside of the refund rules we’ve described, you can ask for a refund anyway and we’ll take a look.

You will be issued a full refund of your purchase within a week of approval. You will receive the refund in Steam Wallet funds or through the same payment method you used to make the purchase. If, for any reason, Steam is unable to issue a refund via your initial payment method, your Steam Wallet will be credited the full amount. (Some payment methods available through Steam in your country may not support refunding a purchase back to the original payment method. Click here for a full list.)

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It doesn't cost nothing - it costs time and convenience to create different accounts and log in to them all separately when you want to change which account you are using.

I searched through the User Agreement. I think you're correct in that this is not specifically prohibited. Similarly, using multiple accounts to purchase multiple copies of the same game and multibox is not specifically prohibited (to my knowledge).

If you are the kind of person that would actually want to play different games at the same time, it does make sense. However, I cannot think of a legitimate reason to actually want to play multiple different Steam games at once. I have a hard enough time being good at any 1 game I'm playing.

Should you be doing this? In my opinion, no. I use the community-oriented features of Steam all the time and the Cons you list would affect me greatly. Having multiple accounts would be a tremendous inconvenience for me, and I don't care about any of the Pros you list.

Exceptions: There may be some games where it would make sense to have a separate account for just that game. I hear you do a lot of sitting around in games like Eve Online; perhaps you would want to play Bejeweled while you wait for something to happen?