One thing I do not get is why Army leaders in the past milleniums weagermess of seizing fortresses instead of going around them. I believe more and more that this paradigm of "We must take this fortress at any cost" included World War I and later. It is just bad leadership.
In the first case I see no viable reason why General St. Anna let his men storming against the Alamo mission just for capuring a fortress from which no reinforcements could be sent because the defenders were already low on resources and manpower. If the Mexican troops just passed the Mission and proceeded to Textas provisional capital at that time, San Felipe de Austin.
Concerning Verdun I still wonder why no one of the German High Command had the idea to ignore the defenders of the town and its surrounding fortifications like Fort Vaux and instead taking another side route to Paris. The French forces around Verdun were so fixated I do not believe that they could have stopped the mobilised German forces.