The former will get you laid, the latter will get you nowhere. Not giving a fuck is not about being rude or aloof, it's about not treating her like a princess that you're lucky to be talking to. Let me tell you right now that she's lucky to be talking to you, pal, and as long as you keep that frame of mind you will be miles ahead all the other chumps out there blowing smiley faces and exclamation marks up her ass.

Here's why: No matter how great you think she is, she doesn't see herself that way. More likely than not she doesn't even really like herself, which makes all the white knight, nice guy chumps seem either dumb or deluded, neither of which are attractive. Talking to a girl or treating her the way you would a buddy or a much less attractive girl is your best bet for catching her interest and differentiating yourself from every other thirsty dude that texts her.

Exhibit A: https://m.imgur.com/nxVSBWR

Met this girl at a bar, asked for her number in less than a minute then walked away once I got it. Every word you say is one she might not like so generally be terse and she'll think you're mysterious. This means not taking a stance* on divisive issues, getting into your backstory or generally being a windbag. Talking yourself out of getting laid is in my experience the most commonly made mistake. Use texting for setting up in-person meetings and nothing else.

Now get out there and take that beach, soldier.