I don't remember the exact battle (perhaps Messine?) but when I was studying it I was fascinated at the concept of defeating trench warfare with the "bite and hold" tactic. All defenses were planned assuming the assault would try to breakthrough and encircle...

... bite and hold just took the next trench over, then fortified it against the counter-attack. It gave the attackers far more time to create defenses and the defender was basically assaulting another trench line, but this time with no trench of their own to fall back to