I believe it is not so much the Sultanate that is intriguing to me but the fact that Brunei is one of the smallest countries in the world and therefore I’d say one of the more challenging stamps to get in the passports. You wouldn’t just fly all the way from Europe just to spend 3-4 days in Brunei (or at least I wouldn’t).
So typically you take the chance to visit when you are in Malaysian or Indonesian Borneo.
Having said that, I recently took the chance to visit Brunei while being just around the corner in Malaysian Borneo. Depending on your port of departure you can either fly in or take the ferry. I choose to take the day-long ferry trip from Kota Kinabalu (Malaysia) and arrived in Bandar Seri Begawan (but everybody just says BSB) in the afternoon.

The heat strikes me every time I get out of an air conditioned room/space but happy to have an incredible new stamp in my passport I make my way to the bus stop. One hour later I’m in Taman Haji Sir Muda Omar Ali Saifuddien Square in the city center from where I find my way to the waterfront. Small boats bring passengers from the city to the famous Kampong Ayor village ($1, 30 second ride). Wind blows in my face and crossing the river my heart is full of joy as I feel like a true traveler again, sitting amongst locals and smiling in faces from a different world, different culture and different heritage.
My Airbnb accommodation in the Kampong Ayor watervillage is simple but beautiful and clean and the lady of the house is very friendly and happy to give me lots of tips. For the next 2,5 days I:

 
Wander around the massive water village Kampong Ayer,


Visit the night market

 

Visit Mosque Jame’ ‘Asr Hassanil Bolkiah


And the famous mosque Masjid Omar Ai Sifuddien.

Unfortunately I (as a tourist) were only allowed to see the mosques from outside as they were prepared for something (I assume the National Day of Brunei). My last day in Brunei was the 23rd February the countries National Day. His Majesty the Sultan and his peoples meet in Taman Haji Sir Muda Omar Ali Saifuddien Square where a several hour long parade is held. It seemed like the whole country comes to march: school kids, the military, fireman, police forces and business man and women from foreign offices even hockey players. Each one of them is wearing their typical ‘uniform’. In small groups and with music in the background they would march over the Square and show their respect to his Majesty the Sultan and his family. I watch the parade for about an hour but leave when it starts pouring. Also I feel like I’d seen it all as people were marching all the same for 1 hour.

In the afternoon that same day I leave Brunei Darussalam for Miri in Malaysia by bus.

A short but interesting trip, filled with lots of friendly and smiling people.