You know it well. The Australian/Valley-Girl tic of making declarative statements sound like a question: "So I went to, like, the shop? And, like, saw this dress? And it was, like, so cute? I, like, had to buy it?"
Intoning every sentence as a question makes you impossible to listen to or take seriously.
Don't be one of these apologist cunts who excuse this bad verbal habit saying it's a natural evolution of the language that somehow shows sensitivity to the listener by checking to see if they've understood. Because it isn't that, and even if it was, I'd call that "condescension".
The constant yoyoing of pitch is a way of making the listener pay attention, something like the whine of an annoying child or spoilt dog. It is narcissistic approval-seeking, and a petty, continuous attention-grab by the vacuous. It is a verbal probe in search of ego-stroking nodding heads and murmured assent. It removes every shade of intonation from proper elocution and turns your speech into the equivalent of a flashing advertisement. It is mentally taxing, forcing you to repeat mentally what you've just heard to parse the grammatical structure.
This used to be an exclusively pubescent female thing, but now you seemingly can't avoid it from people of any gender or age. But you still sound like a pubescent female to me and so I'm going to consciously accessorise you with a a small, pink, Swarovski-studded handbag and "Princess" T-shirt.
I am going to make an actual suggestion here. When the people you know and care about start to do this: Call them out on it.
I want teachers punishing children to prevent it becoming standard English. I want parents soaping mouths. I want friends playing games that involve inflicting pain on offenders.
Get to it.