Polite or Passive?

Does saying things like:
‘I’m not interested, thank you.’
and ‘Sorry.’ When you bump into me.
and ‘Please be quiet.’
make me polite,
a credit to my upbringing?

Or just a passive
someone to be walked over?

Should I have:
Shut the door
Glared
Screamed ‘Shut it.’?

How do I reach the assertive middle ground
Between passive- aggressive?

I’ve been trying for years.