This is one we all remember. From the get go in the first game, we've always loved putting this punk in his place. He's always one step ahead of you in both his Pokedex and the Gym challenge, and never misses an opportunity to rub your face in it.
You've battled Blue several times so you kind of know what to expect; his Pidgey, Exeggcute, Growlithe, Rhyhorn and Abra have evolved into a Pidgeot, Exeggutor, Arcanine, Rhydon, and Alakazam (Psychic was super overpowered in Gen I and this guy was a beast) respectively. And then last but not least, I tossed out my Charizard to take on his Blastoise, echoing our very first battle together. Like Cynthia, it's really hard to compare to the moment where you dethrone this guy.
In the sequels (Gen II) Blue has taken over the now-vacant Viridian Gym, and while he's not nearly as much of a jerk, he's still the same old cocky punk we loved to hate. The Pokemon Origins adaptation (which is great, and you should watch it) made him out to be a little less arrogant too.
Fun fact: Despite the fact that he's not really a punk at all, I've named Blue (you can name your rival, Blue is just the default name) after my good friend Stormy every time I've revisited the game.