Group Ash, Misty and Brock is who i enjoyed the most.
All three worked as perfect true group of comrades with their various types of personalities supplementing each other well making interactions always being full of comedy, drama and lot of care. They came of as unforced, natural characters joking, laughing together, sometimes getting on each other nerves but also showing to be sensible when their friend was in danger often reminding me of persons in real life developing strongest bond out of all groups we had imo.
From Ash naivety and stubbornness, Misty temper, sarcasm and romantic side mixed with Brick flirty, irrational and wise behavior made their chemistry complete and full of ardour.
The original trio had great chemistry; Ash being a noob, Misty being happy to correct him, Brock being a mediator but more his own person with goals of finding his place in life than in later seasons. Misty did mostly mellow out by later Johto and both she and Brock were more ignored as the focus was on Ash and his solo achievements rather than his time spent learning.
About Misty becoming abit more calmer, personally i found that as positive thing being reflect of gradual character development she went through.
Misty there viewed her friends as new family which accepted her for who she was not having to justify herself and live in someones shadow like it was case with older sisters. While still being full of witty comments and competitive streak, spunk not letting others to put her down like Dorian, Egan Ash etc, got annoyed and frustrated with her pokemon like Psyduck, when they were late or embarrassed etc. With more of her other traits which were often overshadowed by temper being showed more like sarcasm,her humorous side,kindness and determination etc.
I noticed in leaving episode how much she grew . She was still feisty and sarcastic, but also developed high doze of responsibility and appreciation for her friends wanting to stay with them and continue pursuing her quest but also realizing how its her obligation to go back and save gym from shut down doing unselfish act.
She and May are my favorite girl companions and i miss her flamboyant dynamic leaving while being left more to be desired about her story and dreams like water master goal.
Hopefully they will return again, at least for appearance.