What does it mean when people use the word "we" all the time?

Like "we" need to pick that up from the store, or "we" need to get the lawnmower running, or maybe "we" should call him? This is not something that involves me. Do you think they are trying to push off responsibility or do you think that is a co-dependant person? I have to correct her all the time, I just want to know what her psyche is thinking.