Norway and Norwegians have a number of customs that may differ notably from the visitor's home country. Here's a preliminary list:

Food, meals and alcohol

  • Norwegians usually eat a quick lunch (bread, coffee) around 12:00, and leave work/school around 15:30. 
  • Bread and potatoes are basic food stuff in most homes.
  • Open sandwiches (slices of dark bread with meat, jam or whatever spread) is a the most common way of eating.
  • Many Norwegians eat whale and find that perfectly OK. (Avoid the topic unless you want a heated discussion.)
  • Most people eat dinner at home around 17:00 or 18:00. Late dinners (like in Spain) is unusual.
  • In the country side, some people eat dinner at noon and go back to work after a good nap.
  • Danes can drink in the morning, Norwegians don't. There is a tradition of not drinking on week days. Don't expect to be offered wine or other alcohol in private homes, coffee (or tea) is standard. A lot of Norwegians get rather drunk on fridays and saturdays, but alcohol consumption is on average modest.
  • Beer is the only alcohol available in shops at restricted times. Wine, strong beers and spirits can be purchased by the bottle only  at the state liqour store (Vinmonopolet) which may not be easy to find. Ask any Norwegian they know how to find them. First time visitors are often shocked by Norway's alcohol price structure.
Manners
  • Keeping calm and not displaying strong emotions in public are common virtues in Norway.
  • Despite the emphasis on modesty, Norway mostly has a low-context style of communication.
  • Although the feeling of being one nation is strong, there are strong individualistic and egalitarian attitudes, being self-reliant and equal is highly regarded. Norwegians are not impressed by titles and formal positions, and are famously direct (getting straigth to the point) and informal.
  • Authoritarian manners are disliked and will cause disrespect. Boasting is disliked.
  • Being punctual is a matter of showing respect. Very important for business meetings (better arrive 5 min too early), generally important even for private appointments, for formal dinners it is acceptable and even customery to arrive some 10 min after the given time. 
  • While informal, Norwegians generally have a reserved body language and may appear as cold or aloof. 
  • It is not customery to bring children to social gatherings in the evening. Bringing children to cafe late at evening can be perceived as child abuse or neglect.
  • Work and leisure is kept strictly apart. Business partners are rarely invited to private homes.
  • Norwegians are generally modest and easy-going, and don't adhere to strict codes of politeness. Note however that table manners are important, like thanking the host/hostess.
  • Words like "sorry" and "please" are not used frequently. Once used, polite remarks are sincere.
  • Norwegians greet with a firm handshake. Sincere thanks are also by the hand. Cheek-kissing is uncommon except among very close friends (then more like a gentle hug). Formal business meetings are often introduced and concluded with short handshakes.
  • Men always stand up giving handshakes, elderly are not obliged to stand.
  • Although Norwegians may be reserved, Norwegians are also informal and can be surprisingly direct, not too much "beating around the bush". Silence don't need to be embarassing. 
  • Norwegians can say "yes" as an intake of breath.
  • Silence is not embarrassing.
  • Formal dinners (such as weddings) are long and often include numerous speaches and plenty of toasts ("skål").
  • Before leaving a formal party, it is customary to shake hands with the host.
  • Condolences (in funerals) is also with a firm handshake, slightly prolonged to express empathy).
  • Norwegians usually take of shoes when entering a private home (unless offered to keep them on). Particularly important in winter as dirt, slush and salt may ruin the floors. For formal parties in the winter season it is possible to bring an extra pair of shoes.
  • Many Norwegians prefer cool bedrooms and typically sleep under warm duvets. Blankets are uncommon
  • In Norway, a "sunday walk" is not a 15 minutes walk to the pub, it is rather a 5 hour+ walk in forest and hills (particularly in the country-side, less so in the city). Norwegians take great pride in being sporty and fit. 
Dress codes
  • Norwegians are notoriously informal, particularly in clothing. Norwegians don't usually dress smart for work and rather casually most of the time. Although some may dress up for a restaurant visit, casual dress is fully acceptable virtually everywhere.
  • Norwegians find it perfectly natural to wear sport clothes and rucksack anywhere.
  • Norwegians generally don't dress very formal. Blue denims are used everywhere. if you somebody with a fashionable suit and tie (in the midle of the day), it is probably a real estate or stock broker.
  • Norwegians don't hesitate to strip down to bikini or short pants in warm, sunny weather. Don't be surprised to see shoppers in bikinis and short pants only.