I have to say we found Arzak a real disappointment. We did all three, three-star restaurants in San Sebastian earlier this month. Akelarre and Martin B. were delightful, each in its own way. From beginning to end, we could not believe Arzak ever qualified for even one star.
On entering, we were invited to seat ourselves in a small lounge/bar at the entrance. Over the next 15-20 minutes, several other parties joined us. Each was asked if they wanted drinks. If so, they were served. Then we had the pleasure of sitting there, watching one gentleman play with his computer screen at the bar, apparently setting up something (seating?) for the night. Various people came in and out, talking and looking at the computer screen. All ignored us.
Finally we were seated. Like many American posts I've read, we were denied non-smoking because it was "full." However, no one near us smoked and so it was not a problem.
Although every plate looked like a work of art, as one would expect at a starred restaurant, the taste just wasn't there. Dish after dish was a major disappointment. Meanwhile, staff would bring the wrong dish to the wrong person, seem confused, and have occasional debates/discussions over dishes that were coming out of the kitchen; these would be off to the side, but in full view of the diners.
The chef, Juan Mari, was out of town, but his daughter, Elena, was the one bright spot, continually bouncing back and forth from the kitchen to the dining room. She was very helpful in recommending choices and even substituted for one dish that I found completely unappetizing. Alas, it was to no avail.
We enjoyed delicious meals of pintxos (hors d'ouevres, essentially) at a number of the excellent bars in San Sebastian for a fraction of the price we paid at Arzak. All were superior to the meal we had here.