This happened twice to me recently, both with Better Call Saul and Silicon Valley, and it elated me each time.
For both shows, I watched what I thought was the final episode of the current season. My mindset throughout the entire episode was that I was watching the finale, and the ending of each was conclusive enough (but with a bit of a cliffhanger) to confirm that assumption.
But I was wrong for both of them. The next week when I turned on my TiVo, there was another episode of each show. I checked the description for each one, which informed me that I was about to watch the real season finale.
This is simply the best. If you’ve never had it happen, think of your favorite TV show. Imagine you’ve just watched what you thought was the final episode of the season. There’s no doubt in your mind that you have to wait another 9-12 months before watching another new episode. Then, a mere week later, you already have a new show! How awesome is that?!
I look forward to this happening again in the future.