Do you signal prior to braking or brake and then signal? I personally like to signal first. I think it's more noticeable and gives them more warning.
I find it quite confusing when people brake without signaling first. I'm looking for danger, e.g., an animal in the road, when that happens rather than focusing on the car in front of me and the next move they make. And some people just take their foot off the accelerator — no signal and no brake lights — and that's especially confusing.