I hate that you need a Google account to use it. I generally don’t mind creating yet another account on the internet since one can easily create such accounts with temp. email addresses, for example; but with Google is trickier (sometimes they even ask a mobile phone number and all when signing up), and I prefer not to have a dummy google account which I use alongside my real google account for fear of being locked out (e.g., google may think “this guy has two accounts, same computer same ip… let’s ban him”)