Cologne (Köln/Keulen) has one of the most festive Christmas markets within easy reach of Wassenaar (about 3 hours drive).
More precisely, the city has about 6 separate markets. We visited the largest three outdoor markets. There's nothing like a little holiday cheer in the shadow of the magnificent cathedral (Dom).
My theory is that glühwein not only warms you up, but gives one the courage to navigate through the throngs of people mulling over the thousands of christmas wares on display. It may be crowded and commercial, but the combination of the scenery and the festivity of the season manage to prevail.