Pushing in subways is the rule , especially the chaotic peoples square station where lines 1,2,8 intersect . Just dig in and push ,don't feel sorry.Bumping into people in streets is commonplace and should not be a reason to get angry. Howerver compared to public transport in other chinese cities , the Shanghainese are better at letting people alight first and the mad rush for empty seats is not so bad. Your behaviour should follow the  situation : if the station is crowded then pushing is acceptable , but if not then you are more like to be looked upon as an" uncivilised foreigner" also , outside the busy times  you should stand to the right on the escalators to allow people to pass.

Because of Shanghai's international status and large expat population , foreigners are less likely to be stared at than in any other smaller cities unless you are in the distant surburbs or an area where many out of towners congregate i.e : bus and train stations.