Everyone is annoying sometimes. Some people are painfully annoying, a lot of the time.
Being annoying isn’t the same as being mean or sadistic.
Mean people are generally annoying; annoying people aren’t necessarily mean.
Sometimes it’s impossible to avoid annoying people. Sometimes people don’t realize they’re being annoying. Sometimes people know they’re bothering others, but don’t see any alternative. Sometimes the annoying thing is physically involuntary. Some people don’t have any non-annoying ways to communicate. Sometimes being annoying is a side effect of doing something else.
There are any number of other reasons people might be annoying. Sometimes people are annoying for the sake of being annoying, but often there’s something else going on.
It helps to keep in mind that being annoying is not the same as being hostile.