I once spent more than 40 minutes in a Parisian train station trying to find a platform; had to ask for help multiple times, all the signs pointed to a general

I once spent more than 40 minutes in a Parisian train station trying to find a platform; had to ask for help multiple times, all the signs pointed to a general direction across a hall. A couple weeks later I was in the London underground, felt like I could not get lost there if I tried.