You become more relaxed once you can feel confident that your settings are good and the drone behaves as it should. However there will always be occasions when you break into a sweat and you start clenching when something pops up and you're not ready for it...
Like pushing the battery trying to break a PB for distance and seeing the battery voltage fall off a cliff.
Like flying with the wind knowing full well that coming back is going to end in tears.
Like trying to get that video/photo out of direct LOS and seeing your control signal disappear and hoping your RTH works as per your settings.
And so it goes....
Having said that, I've crashed and burned planes, helos and gliders over the years and have yet to lose a phantom. Believe me I've tried......