'Could' not 'should'

I got some advice today that will hopefully turn out to be quite helpful. It was suggested that instead of using the word 'should', I use the word 'could'.  I think it might prove harder than it seems, especially since in the last sentence I almost used the banned word. As another example, I was thinking about what I would do when I got home and I was thinking I should vacuum the cat fur off the floor. Then I rephrased it (as I should) to: I could vacuum the floor. This also made me realise that 'shouldness' is a state of mind that goes with perfectionism, which I have in spades. I put expectations on myself, often unnecessary, then I beat myself up emotionally for not meeting them or putting off plans. Hopefully avoiding should might help this self-pressure.