I love watching my betta casually cruise around the tank, under and through the plants/scape before stopping for a rest and repeating the process. He just looks so content taking his time exploring every square inch of his tank, it makes me happy to see.
What warms my heart is when my baby cories watch their parents eating a huge pellet, and then, they try to eat it. The fact that it is as big as their head makes me smile. It also warms my heart when my leopard bush fish "parks" himself in his cave. He goes slowly around the side, then as he turns, he puts the pedal to the metal and zips on in. He's a big goofy guy, not the smartest but adorable. <3