hmm, not sure if I understand the question - do you mean what stopped me from being more assertive with her sooner, like to say 'This topic and the way you approach it so casually and in a loud way is making me feel uncomfortable' or to say 'Let's change topics?' when she was going on about my work history and how I called her crying (I didn't want to be called a sissy, or something like that, plus she had called me crying about her job problem/s too), when she spoke about my mum that way - I was crying and 'in a state' so I didn't even contemplate trying to get assertive...

The whole car trip was stressful for me, partly because she was occasionally smoking (I'm a non-smoker and for healthy living) and throwing the butts out of the car window (and she says she LOVES Nature!!) partly because of some other things... It just added up, I guess... She can get very 'defensive' (and loud) if confronted (like with the cigarette butts), so I preferred to not get into a direct confrontation with her when possible. But talking via texting was acceptable to me, even if she used some 'loud' language/'rolling of the eyes' or such... (she can't be that 'loud' via a text message! lol)