You're in a conversation with a group of friends. Someone brings up the topic of TV viewing habits. One person says that she's thinking of canceling her cable subscription. You don't have cable, and you don't think you need it. You say:
I'm perfectly fine not having cable.
If you're "perfectly fine" with something, it means that you don't have any problems with it:
If you want to smoke in your own home, that's perfectly fine. But other people shouldn't have to breathe in your smoke while they're trying to enjoy a meal at a restaurant.
"Perfectly ___" is usually used to disagree with what someone else said:
A: Stop getting upset.
B: What are you talking about? I'm perfectly calm.
Or you can use it to express a contrast between two ideas:
You state an action that you're perfectly fine with by saying "I'm perfectly fine ___ing":
I'm perfectly fine just staying home and chilling out today.
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