My first thought was why is it only Taichi and Chihaya crying. A display of gross imbalance in the trio’s friendship; Taichi and Chihaya is more emotionally invested in their relationship. In a situation like that, getting a little misty eyed is normal. Didn’t really need Arata’s teacher to tell us he was very nervous about meeting them. I think it’s obvious he’s the type that internalizes his feelings. Then again it’s hard to warm up to a character that’s featured so infrequently and given a godlike status by his friends.
The most profound scene from E20. Brilliantly combines the weight of sound and karuta card to infer Chihaya likes Arata because she only thinks of him. Subconsciously of course, she’s perfectly oblivious to romantic feelings. The card applies to Taichi too. For him, there’s no other rival except Arata and the guy is absent for the majority of the anime. Though he despairs of being eclipsed by Arata he decides not to be a coward or take the easy way out like he did as a kid, so he turns down the doctor’s offer to bend the rules and promote him to Class A. If only Chihaya would show more character growth. She’s still so dense.