1. always keep a copy of visa page in case of passport got lost. Consulate in SF might be able to issue me a china visa if I have a copy of the visa page which I do not.
2. before you leave canada, always apply a china visa even you do not plan to go back china in near future. So you will be able to send you passport to a travel agent to get your visa if you get a new passport otherwise you might have to go back to canada yourself.
3. apply a china visa in consulate where you live even you do not plan to go china soon. they are able to help you if you have applied visa there before.
4. they ask to book airline ticket before you apply visa. so if you do not plan to go china soon, buy a refundable ticket. and get your money back after you get your visa.
5. I do not think that consulat in SF tried to give me a hard time. They are really nice but they have to do what they are asked to do.
I visit this website often and got a lot help, especially from xiaobaitu and pijiang. I just want to give something back. Good luck to erveryone.