A few years ago, when I only started using Bitcoin, I've lost a small amount when I sent bitcoins to a wrong address.
I think it's not lose big,this may be a small thing but a lesson for us all,to see the wallet again send,because a little mistake will be worse in the end,missing something though a small but worthwhile.you are still lucky people to lose a lot for playing gambling,ponzi games and scam mining sites.
I always check the first and last 5 characters of the address I'm supposed to send it to and compare it with the address I pasted. You too should get into a habit of double or even triple checking the receiving address. That way it will be very unlikely to send to the wrong address.