From my perspective as a cyclist (and I drive daily), I'll note that in this jurisdiction, the rules of the road say that cyclists have to stay as far to the right as "practical and safe."
1. If the road I'm on has a shoulder, that's where I ride. <-- out of the way of traffic
2. If the road I'm on has no shoulder, but a wide traffic lane, I ride on the right. <-- traffic can pass me safely
3. If the road I'm on has a narrow traffic lane, I generally ride in the middle of the lane. <-- traffic has to change lanes to pass me.
In scenario 3, I can understand traffic getting angry that I'm taking up the lane, but here's my perspective: it's a narrow traffic lane, so a car can't safely pass me without changing lanes. I have been hit twice in this manner (nobody ever stopped; thankfully I wasn't injured, but their cars were scraped by my handlebars), and had several close calls.
Since it's unsafe for them to pass me while staying in the lane, they should change lanes. So if they have to change lanes to safely pass me, I might as well ride in a manner that forces them to change lanes. So I ride in the center of the lane.
If the driver is in a rush to get to the next traffic light, they can change lanes and pass me SAFELY. So far I haven't encountered any psychopaths who are willing to completely run me down. Assholes sometimes honk.
One other situation gets me riding in the middle of a traffic lane: parked cars. I've nearly been "doored" several times, so I ride SAFELY away from parked cars. Many drivers don't check the mirror for cyclists before opening the door. Rear passengers NEVER check. If the lanes are narrow, it might mean that I end up riding in the middle of the lane.
All that said, I try to avoid roads where I know I'll have to ride in the middle of the road, and especially if that road goes up a hill. And one thing I NEVER do is pass cars in a narrow lane at a red light-- if they've taken the effort to pass me safely, I'm not going to slow them down again. I'll only pass them if there's a shoulder.
As far as dedicated bike lanes or paths go, if they are close enough to be useful, I generally use them. As long as it's not one of those meandering routes with kids and off-leash dogs. Putting a cyclist who's doing 30-40km/h on one of those paths would be dangerous.
One other note: as much as drivers might be frustrated by my presence, I don't really slow them down. It takes me about 35 minutes to drive to work. On bike, it takes 38-42 minutes, depending on my luck with traffic lights. It would be quicker if I took the main roads, as the bike routes have a lot of stop signs. And I've got a big hill to climb (~90m elevation gain) along the route, with stop signs every second block on the way down.