You have to understand that you were sailing on NCL - their motto is, "You're free to.... whatever." So you'll find everyone is alot more casual in their attire for everything.
They don't have any 'formal' nights like most of the mass market cruise lines do. If you like formal nights, then you really need to try some other cruise lines. Depending on your age and lifestyle, you might prefer a little more upscale cruise line. My personal favorite is Celebrity as it's alot nicer with MUCH better food, and is definitely more upscale without being 'stuffy'.
47 Cruises & Counting! Favorites: Paul Gauguin to Tahiti: Uniworld River Cruises in Europe; any of the Celebrity Solstice-class ships; Holland America for 12-nights in the Baltics & Russia; RCCL for 14-night Greek Isles, Turkey, & Croatia; Holland America for 14-day Alaska cruisetour; 10-night Canada/New England cruise; 21 days in Hawaii including a 7-night NCL cruise; Oceania for 25 days in Asia; & 3 months touring Europe by train. And many days spent in all-inclusive resorts!