I had originally synced all my phone to my iMac the first time i purchased it. And then cause my sister synced hers as well and all the contacts got mixed I just deleted them all off my address book and tried to sync my phone back again.

However when i tried that iSync deleted all the contact from my address book and the only 2 that remained were the contact I had added that day on my phone.

Luckily i had a backup on my ipod and then added my contacts from there and put them on my phone. This has however raised some serious concerns for me

1. Why did that happen?
2. When contacts are added from the phone to the computer one is given details about which are the contacts, events etc and you can either sync that or not; however there isn't an option to just sync particular ones like in windows. Can that be done?
3. Is it possible that when the iMac is making changes to my phone is have the option of accepting or denying the changes? Like is provided in windows.