I always make sure I hold the door open for people - but when I'm trying to manuvere (sp?) a huge pram into a small shop and no-one tries to bother to help (we've got a Subway with a small doorway that the pram only just fits into - its one of my fav places - and there are seats near there door where people regularly are sitting) it makes you really think 'If no-one does it for me, why do I bother?'
If DS is crying in the car, I won't let other cars through, in or out - I just can't tolerate his crying sometimes and its hard to concerntrate if he's crying in the car.
And if I have a huge trolley of things, same as LZ, it depends on how DS is - which, most of the time, he's pretty good when we're at the shops