Don't even bother to guess which actor this is. Dick knows all the TV shows I watch and he just stared and stared at it until I got impatient and told him.
It's like a bad game. I draw someone, he ponders and doesn't guess, I tell him. After this sketch from a couple weeks ago I've stopped showing him.
On the other hand when I draw a bird or dog or a puffin in the zoo, he knows exactly which one I'm drawing—so what's up with that?
It doesn't matter. The point I'm trying to make is don't over think it. Some people are going to immediately recognize who it is you're drawing and you'll have a successful life as a portrait painter. Other people are going to simply smile and hold their breath until you tell them who it is you drew.
Sometimes people pay me to draw people and then I take much more care, study a lot of photos, study the person (if they are alive), make lots of sketches, and then make a drawing that looks like the person. Everyone is happy.
But what I enjoy more is simply looking at someone (or in this case the TV) and just trying to capture something very, very quickly. That's more fun for me. I can look at the finished sketch and say, "that bit is right there; I really like that bit over here; oh, that bit didn't work at all."
What has happened is I've created a dialog with myself about looking at that person's face. The sketch is that dialog and it contains some details about that person, but it contains even more details about what I think about the process. So when I look at that sketch I see where I want to go in my process.
That to me is more important than someone recognizing the person I drew. I bring this up to suggest you consider how you view your "failed" sketches. There's a lot of good stuff in them that you can enjoy, and the enjoyment of that good stuff will push you along to make more sketches, containing even more good stuff. And isn't the search for more good stuff ultimately more rewarding than pronouncing something "failed"?
If you shift the way you think about your sketches you're going to make more of them and as a consequence you're going to find more good in them.
And one day you might be at a show of your work and someone will come up to you, point to one of your paintings and say, "Hey, when did you meet my dog? That's him over there on the wall."