Or people who try to bypass traffic jams when the road splits. Take the A1/A194 north bound at Washington. 3 Lanes of the A1 blocked down to the Team Valley, so you have some entitled pricks who think they are above joining the queue like everyone else, head into the rightmost lane for the A194, race up passed all the traffic, get to just where the road splits, stop in the middle of the road and try to cut in. As well as pissing off all the people on the A1 who actually queued, now they have blocked the A194 for no reason. Basically "I'm too important to wait in this jam, let me jump the queue, and to all you who want to use the A194, tough shit, my queue jumping is more important than any of you".
(Nerd ramble alert)
As for the second one, I did a 5 minute talk on a conference on this, as it also comes in to robotics trajectory planning. Imagine a path of people, and around everyone you can draw a circle of how much space they take up, plus an acceptable amount of personal space. You also imagine a triangle on the ground coming out of that person showing where they might be in the next 5-10 seconds. I have not got one of the diagrams to hand unfortunately.
If the person is physically large or say it is a couple arm in arm, then the circle around the amount of space they take up is large. But also if they have large bags or they are one of these people who swing their arms massively when walking, they just take up more space.
Then for this triangle coming out of them. The faster they go, the longer that triangle will be, but the more certain of their direction, the narrower the triangle will be. So take a cyclist, on a bike is usually a fairly thin object and most of the time they will be travelling in a dead straight line, so although they are fast, you can imagine a long but fairly narrow zone in front of them of where they are most likely to be in the near future. So you don't walk into that imagined zone and you are fine, the fasts moving cyclist becomes less of a collision risk, but higher consequence if you do collide.
But then you get to a fat, arm swinger zigzagging, they take up a lot of the path anyway, but because you don't know if they are going to go left or right at any given time, the zone in front of them is quite wide. If you are walking faster and for personal space and collision avoidance, don't want to go in that zone, it becomes a really wide target to avoid. If they are in the middle of the path, it means only the edges are clear. But then if you have one or two people coming the other way the zones in front of them might fill in the gaps around this zigzagger and you have this odd scenario. Although there might only be 2 or 3 people on a very wide path, to be certain of avoiding them and being polite the path is actually blocked. If the same people were walking in a dead straight line, the path would not be blocked.
That is how robots see the world. Try to picture that prediction zone in front of people next time you are out. It is one of those little mental pass times I find interesting, particularly if I'm doing something like going out for a run when my mind is just wandering anyway, but I'm more sensitive to people in the way, because if I slow it is a lot more effort to get up to speed again.