When emotions are running high, hurtful words can be said which in ,any cases, one might be unable to come back from, as the saying goes; “When emotion goes up… intelligence goes down.”
This immediately makes the speaker sound like he is god over his or her partner. The word must, makes you seem like you are in complete control and only what you say must be followed or adhered to.
The word expect in a sentence to your partner sends an accusatory message which in turn puts that person in a defensive/failure mood.’I expected you to do it…’
When you make sentences like ‘I assumed you …” it simply means you feel the person is dumb to have done a certain thing.
Using the word should means you are asserting your authority in a relationship which is believed to be on equal bases.
“You never do……’ it will only create a crack in your perfectly guarded relationship. Its an accusatory word.