Worrisome? I don't really know you well enough to give you a specific answer.Why does Firefox always set Google cookies, no matter how I set privacy or use a cookie blocker? Are these cookies worrisome?
Obviously Google's main source of revenue is obtained by tracking your online activities and selling that information to clients who want to sell their wares to those that seem most interested in what they have to offer. If, for some reason, you object to that, then I guess you should worry; otherwise, it might help eliminate ads for things you have absolutely no interest in.