Apple Users

I love iCloud too...but, when I hook my iPhone up to my computer, I do not want my contacts to sync, therefore that box is always unchecked. However, occasionally I open my contacts on my phone, and they have been synced...and I end up with tons of people's numbers and email addresses that I manually remove...I only keep in my phone the numbers I need frequently.
And, I've had two iPhone 4S's..they both did this. When I am on my macbook, I constantly get the Sync Contacts screen which tells me that I will lose some contacts and asking if I want to continue...I just say no...but it comes back later.

I am a long time Apple fan, but not technically savvy...so forgive my lack of understanding.