Why the hell does Google navigation always want to calibrate the phones compass when I just started driving?

Is it programmed like "Oh, didn't expect him to actually drive after he entered his destination, now quick, let me catch up on it now"?

Hmmm. Haven't experienced that.

It happens every few uses and I don't understand why it doesn't check the compass at start.
It's a Samsung device, so it may also be a cheap sensor which loses calibration too often, but I don't even care about the compass function, it's mainly to show the current direction on the display.
But it's really pointless. I start Google Maps, enter the destination, start navigation, put the phone into its mount, start driving and after a few hundred meters it shows the calibration message which tells you to turn the phone in all three dimensions for some time. I don't want to stop to do so and I surely will not do it while driving.

@ddephor yes, it could be the phone. I have the Galaxy S7, and I haven't encountered that issue, but I normally use Waze for navigation, and not Google Nav.