The worst is finding out your tube has a removable core AFTER you've pumped it up to 120psi using a tiny, crappy micro pump - you learn this when your tube deflates as the removable core has come off when you were trying to unscrew the over-engineered POS Lezyne chuck from the valve. When it happens a few times, you discover a whole new level of frustration. Just sayin'.

Superglue is your friend.

V.