The kid who plays Glenn is a really bad actor
I just watched the episode where he came into the city to see Sally and she ran off cause she got her period, then he came back to Don's and Don took him back to school. Just everytime he delivers any kind of dialogue it sounds so damn wooden and bad, when he was younger i didn't notice it that much but now thats he's a teenager and older its more noticeable.
He always sounds like he's reading right off a cue card or something and puts zero emotion into his lines, he just says them.