Service is one of the key ingredients for a successful experience at a restaurant. It should be friendly as well as attentive.

When I thought about celebrating my birthday with my family at a restaurant, I even entertained the notion that the service should be personal, perhaps even a bit fawning. This would differ significantly from the usual family dinners where at least one of the parents is hopping around the kitchen searching for some missing flavor enhancer for one of the fussy eaters at the table.A private dining area at the Nikko Japanese Restaurant in Sugarhouse was just the answer. While a bit tattered (some of the wood slats from the sliding door were missing, the overhead light fixture needed cleaning and one of the bamboo floor mats was worn), our pleasant, perky waitress made us feel like we were her only customers. She even overheard us discuss my middle-age lament, bringing us complimentary scoops of sherbet for a birthday treat.

Unfortunately, the food we experienced reflected some of the downside of getting old.

Our broth servings, though nicely flavored with ginger as well as bits of scallions, were served lukewarm. Two of the appetizers were also disappointing. The half dozen gyoza ($2.50) had a flavorful meat filling, but the dough skins were uneven - both crispy and soggy. The scallops teriyaki ($3.50) came with a thickened, almost gravylike sauce.

The hot tea, an ordinary tea bag, did not meet our expectations for the lively green-leaf tea we usually enjoy as part of our meal at a Japanese restaurant. The iceberg lettuce with the salads was a bit sodden; the thin rice-wine vinegar dressing had settled to the bottom of the bowls. The scoops of steamed rice were served in very small individual bowls rather than brought to the table in a more traditional wooden rice bowl to keep it hot.

We sampled several of the combination dinners, which gave us a chance to try the tempura, sukiyaki, and teriyaki preparations. The entrees were better than the other courses, especially the chicken teriyaki. While it could have been served warmer, the half, disjointed chicken was juicy with a crispy, lightly glazed skin. The sauce was nicely sweetened and just salty enough.

The tempura vegetables seemed to have been just a bit overcooked; yet they still had nice flavor. Potato, yam and green pepper, were the main choices. The shrimp maintained their flavor; the lobster (we surmise a strip of rock lobster tail) lost any distinctive taste or texture. The dipping sauce was very good.

The beef sukiyaki consisted of thin yam noodles, chunks of napa cabbage, mushrooms, slices of onions, and slices of beef in a flavorful broth. The portion, like the others, was generous in size and seasoned with a pleasant broth.

Nikko Combination dinners are priced from $10.95 to $12.95 for the special which includes shrimp tempura, chicken teriyaki and beef sukiyaki. Regular dinner choices cover the above as well as fish tempura prepared with halibut, beef teriyaki, bata yaki (cooked in a butter sauce) and yaki niku, a do-it-yourself dish.

Broiled or teriyaki-style steaks and seafoods make up a broad choice for diners from steaks, salmon, mahi mahi, hoki, iwashi (sardines) and red snapper. Prices range between $7.95 to $20.95 for the Australian lobster tails. Other choices include sashimi (raw tuna), seafood Stroganoff, oysters on the half shell and king crab legs, as well as several steak and seafood combinations.

All of the Nikko dinners include relish plate, soup, salad, steamed rice and hot tea.

While the cuisine at the Nikko did not have the freshness or sparkle we had anticipated, the service and atmosphere are comfortable, and the prices are reasonable. Perhaps a bit like my own self perception as I became 45.

Rating: * *

Nikko Japanese Restaurant, 2115 E. 2100 South, 484-8431. Open for dinner 7 days a week from 5:30 p.m. Accepts major credit cards and check with guarantee card. Reservations recommended for weekends.