Show, don't tell. Hallowed writing advice, definitely. The whole point of it is to involve your readers. To pick on an clichéd example, writing : "he slammed the phone down" is infinitely better than "he felt angry". By showing, you're inviting your reader to participate in making their own conclusions about the character's emotions
But you can go too far. I see this happening in my own work, and when I'm betaing, when a characters thoughts are involved. Some things have to be told. Prose is not a movie script.
For example, if a person is hovering on the edge of entering a building, they may be nervous, anxious, sort of hoping that the person they're going to meet isn't in there, while at the same time knowing that they need to meet this person.
Fear, anxiety - all that can be shown through the bodies reactions. But the moment you start trying to show the thoughts of that character, you can get stuck. A sentence along the lines of "he doubted he was going to get anywhere with Chris's help, even if the fear screeching at the back of his brain told him otherwise" is fine in this situation. You're telling. You're telling that he's afraid, that he doubts he can go further without this.
But you're also inviting the reader into the characters mind. Something you can't do just by showing. If you say something like "he hoped from foot to foot, hesitating at the doorway", that shows that he's scared. It doesn't show us his thoughts on his fear though. I doesn't show us how he's made mentally as a person.
The whole point of showing is to involve the reader, to make them part of the story. But you can only show emotion, not thoughts. And while actions do make a person individual, thoughts make them unique.
It's entirely possible that there could be two people standing at that doorway, both nervous and scared about going in. Both could go in. But one could be formulating a way to go about his objective if this fails, while one other is totally in the moment, and just hoping to hell that this works.
There's a significant difference between inviting the reader into a person's mind, and hitting them over the head with things they could figure out for them selves. But none of us are mind readers, so telling definitely has its place