Someone asked about barking/growling and attacks.
Attack is a broad term and from the point of view of the victim, the motivation for the attack doesn't matter, they're at risk of injury whatever... but from a dog behaviour pov.. it does.
Predatory 'attacks' - this is where the dog intends to grab, kill and potentially consume.
This is very rare, and usually silent.
Defensive aggression - most aggression is based in fear and desiring whatever it is triggering that fear to go away. So you see lots of growling, possibly barking, teeth bared, potentially lunging to the end of the lead or at a fence (which means people think it isn't fear or defensive but dogs are very capable of bluffing and pretending to be confident in order to drive something scary away).
Frustration - looks v similar to above, sometimes theres a higher pitch to the barking, and growling is much less likely. Some frustrated dogs will be pretty much screaming.
Play - yup, dogs can and will growl, bark, and excitedly scream, in play. Some of the XL bully attacks I have seen on video appear to start in super highly aroused and frustrated play, typically grabbing at sleeves/arms, play bowing butt in the air, elbows down, leaping, and further excited and aroused by the victims movements and shouts/screams.
All of these can be deadly, depending on the size of the dog, their prior learning/experiences, and what happens next.
So a defensive dog if cornered, trapped, held on a tight lead, or in a tight space in a house may be pushed to actually bite if whatever they're scared of doesn't go away.
The frustrated dog behind a fence, if that fence breaks... they might immediately walk away OR they might grab at whatever the trigger is.
Predatory drift is a real thing - you can see a surprisingly accurate depiction of this in the animated film Madagascar, where Alex the lion is running with his friends... and starts to see lots of little steaks instead of friends. At some point the context and behaviour of others plus the hyper arousal of the dog mean they flip into predatory behaviour.
The dog playing, particularly one who has been taught to grab at sleeves, taught bite work by being hit with sticks and encouraged to grab a bite sleeve, could slip into predatory drift very easily and I do think at least one case involved this.
And then on top of all the normal natural behaviours, we have the human element. Where human training/handling has taught the dog to expect or fear certain responses, and so alters the dogs normal behaviour into something abnormal and much less predictable.
A common example is where people punish a dog for growling thinking that will fix the problem - of course the growling is just a symptom of an underlying problem, and the punishment stops the dog growling but doesn't address that underlying cause. So now you have a dog fearful of a particular trigger who cannot warn with a growl. Many dogs will leap straight to a bite, and often it won't be the person who trained the dog that gets that bite, it will be a child or a stranger.