When I played Ruby, Sapphire, Emerald, FR, and LG, I used to restart the games all the time for new adventures and because I mistakenly thought that more restarts = better chances of a shiny appearing. Now I know the value of saving one game for a while to keep good pokemon in, whether to restart other games in or to trade to later generations.
I also used to breed pokemon the minute the daycare center became available in RSE, and I would wind up with a bunch of pokemon with lousy movesets. Now I wait until at least after the E4 so I can breed great moves onto pokemon. Diamond, Pearl, and Platinum were especially helpful with the high-level pokemon after the E4 with great moves.
On the not-so-positive side, I used to play the RSE and FRLG games with the sound on all the time because it enhanced the playing of the game. I also loved the random sounds of wild pokemon. Since Diamond, Pearl, and Platinum I frequently play with the sound off because I detest the bike music in those games. It sounds like a circus. I'll listen to HG, SS, and Black and White's music, but not those three.