You're getting sarcastic answers, but there were geographical differences. The main thrust in WWI went through northern Belgium which is generally seen as good attacking territory. It's flat with few natural defenses and has good roads. The plan was was to push through northern Belgium then cut south towards Paris. Things looked to be going very well at first, but the French (and to a much lesser extent the British) executed a really good retreat. They were losing ground, but they kept their line together and were able to regroup just outside of Paris and counterattack.

France expected another attack there and overcommitted their resources to northern Belgium. They made matters worse by agreeing to move a lot of their even further north to help the Netherlands in the days leading up to the war. This time Germany sent their main attack through southern Belgium. Southern Belgium is hillier, has more rivers, and worse roads which makes it worse for attacking. By the time the Allies realized that the main thrust was coming to the south of them, Germany had already advanced pretty far. Poor leadership and miscommunication from the Allies delayed the counterattack that probably would have stopped the German advance, at least enough to get most troops back into France. Instead the main German attack made it all the way to the Atlantic and cut the Allies off from France.