but i am a Samsung fan. do not care about security
You should if you use your device to bank.
Or if you transmit personal information
Or, if you have a position with any sort of security clearance.
It's only a matter of time now before the Chinese hackers exploit the inherent weakness of the Android and Apple systems and hack their way right into the most confidential of places - the Pentagon, the military, the US Gov't, the banks, the stock market.
But you are correct, if you just use your phone to talk like a dog would, or to take photos and make the people in the pictures look fat, you probably have nothing to worry about.