Ash,Misty and Brock were group which started everything, introduced to us world of pokemon and to this day i can't but not to like their friendship and close bond they build around themselves. They had perfect level of understanding between themselves, lot of moral support and lot of flare, humor and dynamic interactions between themselves with no one feeling left out staying consistently fun for pretty much whole original series period.
Ash naivety and stubborn attitude not wanting to listen to his friends and do things on his own getting into clash., Misty flamboyant, sarcastic nature coming up with various jokes and taunts, while showing herself to be sensible pulling out from Ash his best through bickering, fierce rivalry and showing of they had between themselves packed with Brock who was absolutely hilarious and vibrant as character being supposedly most wise and intelligent group member while having himself issues to deal with finer things in life looking for consolidation among his friends when getting into trouble with girls etc. producing natural, unforced and enjoyable dynamic between characters.
They captured perfectly message of pokemon being about friends which are there for each other, help themselves to move forward or give backbone on which you can rely when feeling down joking with each other, having fun laughing, talking about their dreams and issues comforting themselves and giving motivation not to give up while arguing or being annoyed at each other flaws sometimes just like real friends would do.
I liked how their friendship was strengthened even more over time from Kanto end of Johto developing very strong bond between themselves, and giving out impression of companions which passed through many things knowing themselves for long time with interactions containing lot of comedy, sarcasm and emotion. More than any other group Ash traveled with had in my opinion.
