I think bottlenecks are magnets for oblivious morons. There are several varieties of Narrow Passage. Most are doors. Some are intersections of hallways. More amorphous ones are created by crowds and continually shift. But no matter the species of Narrow Passage, just as you arrive at it, it will be blocked. A very slowly moving person or collection of persons will ooze slothfully into the space mere nanoseconds before you need it. Then they will stand there with no apparent purpose in life, except to have volume. They will look lost, and yet be able to keep their back turned toward you at all times. The more you are in a hurry, the dumber and more slothful they become.
Or, you may be heading down a broad sidewalk at a good clip. Just as you overtake the gaggle of 4 or 9 people ahead of you, they'll drift apart into a sauntering roadblock. Holes between them will leisurely open and close just before you can take advantage of them.
Or, perhaps there is a set of double doors. In all civilized countries, people drive and walk to the right in any sort of traffic. Observation of any busy mall or campus will show that 90% of all people walk on the right. If you make this observation, watch how much chaos that one left-walker causes (and note how he doesn't notice) as everyone has to stop, start, and dodge to get around him. It's worse at a set of double doors. Foot traffic can be flowing at a decent rate, with the outgoing people on their right and the incoming people on their right...until that one inconsiderate, incoming boob with his nose buried in his iPhone stumbles through the wrong door. All the people trying to get out are now stopped (and a crowd quickly piles up.) The sheep behind our hero just follow him and so now there's a line of left-walkers blocking both doors from the people who want to get out.
Maybe they don't teach this in schools any more, but I recall several lessons about paying attention to where one was. If we met someone coming the other way we needed to talk to, it was a matter of courtesy to step out of everyone's way, rather than block off an intersection for 5 minutes.
Don't get me started on HEB or Sam's Club. The aisles are ample for two carts to pass. Maybe even three. Yet there are left-walkers who charge down the aisle and it never registers with them that absolutely everyone is making a curve around them. Or they have to turn their cart sideways and stand next to it while studying, oh so carefully, the labels of everything of the bottom shelf. (These are the same people who take 750 items to the express lane.)
Do you really want your tombstone to read "Here lies Bob. He took up space. But not in a pleasant way."