It depends on the counter offer and your situation. I would have agreed with you, but a couple years ago I told my employer that I had a job offer kind of land in my lap (I wasn't actively looking), that it was good and I was inclined to take it. I wasn't unhappy at my current job, but the change in title/seniority and compensation of the job offer was definitely worth it. They didn't want me to leave, so they countered with a very strong offer, which I decided to take and stay with the company. If you want to leave because you're unhappy with other aspects of your job, then I agree that accepting a counter offer doesn't seem like a great choice.