Satellite photos showed the 2nd and 3rd lines were massively more fortified. Huge anti-tank ditches, concrete bunkers, millions of dragon's teeth, etc. The first line was trenches and minefields.

Commentators thought the 2nd and 3rd lines would be the true challenge because that would be true for a Western army with air superiority. Minefields basically don't matter to nations that can park an instant air superiority boat off the coast of anywhere and just blast anywhere their mechanised infantry want to cross.

We thought the counteroffensive was going slowly because the Ukrainians just sucked at their jobs. Turns out it's because they were doing minesweeping by hand, with infantry, at night - because the British minesweepers they were given either sucked or, again, relied on the assumption of air superiority.

Now that it's a stand up fight again, lo and behold, they are making quick work of the unmotivated, hungry, poorly paid Russian conscripts - who are pretty much all that's left after Shoigu got everyone competent killed in the farcical invasion.