The volleyball club members in Haikyu!! have a way of reeling in fans of the show and even more so when they have wholesome moments with one another. The show, overall, can get intense, whether it's during the volleyball games or interactions between the players.
One of the best aspects of Haikyu!! is the friendships built throughout the four seasons and the ways the team dynamics develop. One of the famed and most wholesome arcs of the anime is the summer camp training arc with the barbecue for the teams at the end, and it brought moments of laughter and moments of realization for major characters like Shoyo Hinata and Tadashi Yamaguchi. The training camp arc isn't the only wholesome part of their story, though.
Beating Shiratorizawa
Without a doubt, one of the best moments and most wholesome in all of Haikyu!! is the shock and subsequent hugging and sobbing that followed Karasuno scoring the winning point against Shiratorizawa.
Daichi, Sugawara, and Asahi are the renowned third years throughout the seasons of the show and it was often mentioned that they might not get to play after InterHigh Qualifiers, so when they burst into celebratory tears after being a "Power House School," it was one of great relief for the players and the fans.
Nutrition
The notorious Summer Training Camp arc led to the subsequent barbecue for the teams and Kuroo Tetsurou’s moment as captain when he calls on the younger players to make sure they’re eating enough. The other captains also joined when they noticed Tsukishima and Yamaguchi didn't have food in their hands.
This scene is especially wholesome when Tetsurou calls out his childhood friend, Kozume Kenma, who tends to be gaming rather than paying attention to what his volleyball team is doing outside of matches. Kenma even tries to act like he wasn't doing anything wrong after hearing Tetsurou yell.
Meat Dance
Toward the end of the Summer Training Camp arc, the barbecue not only gave fans the opportunity to see their captains check in on their players to make sure they were eating enough, but it also gave fans the meat dance, notably one of the silliest moments in the show. This consisted of the three players dancing in line together and chanting "meat dinner" and Kageyama joining, in but doing his entirely own dance.
Hinata, Kageyama, Tanaka, and Nishinoya overhear the news before it is officially announced and instead of being discreet, they broke out into odd, in-sync, dance moves, celebrating the fact that they'll get to eat meat later.
Tendo's Song
In their game against Karasuno, Shiratorizawa's setter, Satori Tendo, broke out into song while on the sidelines to hype himself up about beating the Crows. Tendo is outgoing and odd in the best way from the moment he is introduced to fans. One of his many personality traits is that he doesn't let much get to him off the court, and when he does, he finds entertaining ways to motivate himself and others.
He wags his taped fingers and even tries to get his rather docile teammate, Semi, to join in and it won fans over because the lyrics are about the destruction of the other team but yet the rhythm and tone are still so upbeat.
Bokuto & Akaashi
There are multiple moments between the Ace Captain of Fukurodani, Bokuto Kotaro, and his setter, Akaashi Keiji, that fans consider wholesome, but one of the best is around something that happens nonchalantly and somewhat in the background in both the manga and the anime.
Bokuto loves to make an entrance and in "Land Vs Air," when they are about to play Nekoma, he throws his jacket behind him and viewers get to see the reliable setter and friend, Akaashi pop up and catch it just in time.
Watermelon
Post-games at the training camp, the players would get snacks and breaks as usual, but one day they were treated to watermelon brought by the parents. Hinata had a tendency to make friends in the most unlikely of places and people were just drawn to him no matter how opposing their personalities may seem. For example, Kenma sitting with anyone other than Kuroo or on his own is rare, but when the watermelon break came, he sat with Hinata and Lev even while they were goofing off.
During this break, Hinata & Lev spitting watermelon seeds and laughed at themselves, and there is a wholesome frame of Kenma with half his watermelon sticking out of his mouth.
Tanaka Study Snacks
When the first and second years started to panic about passing their exams, they broke off into groups to study before being allowed to go to training camp or their final tournaments. While the first years went about it in a more intense fashion, asking Yachi for her help and finding new ways to complain about their studies, the second years tried to be focused and somewhat enthusiastic about studying.
Tanaka offered up his house for the second years' study session and Ennoshita, the level-headed and smarter second-year, promptly made sure they focused on their studies. Tanaka is known to be rowdy and encouraging, especially alongside Nishinoya, so even though they had to keep it together and focused, Tanaka also really let his personality shine when he burst into the room with snacks to make sure studying was more enjoyable.
Fly Higher
Tobio Kageyama and Shoyo Hinata have always had an oddly balanced relationship between challenging each other in a friendly way and considering each other rivals. When they first met, Kageyama made snide remarks to discourage Hinata and he didn't really expect much out of the tiny redhead. But as they became teammates and grew together, realizing that they could depend on one another and learn from each other, their rivalry also became a friendship.
So when Kageyama finally encouraged Hinata to “fly higher” after a practice match, it was one of the best wholesome moments Haikyu!! because Kageyama was finally using his words to help his friend rather than knock him down and it was unexpected. This moment on the stairs showed fans the growth of the characters and their relationship. It also led to Kageyama being able to tell Hinata when he did a good job on the court during games, like receiving Ojiro's spike.
Tsukishima’s Block
Kei Tsukishima was never as aggressively into the game of volleyball as his teammates were because of a sore familial issue and the game itself wasn't yet "fun" to him. After realizing his brother had been lying to him about holding the "ace" position on Karasuno's team years ago, Tsuki didn't let the idea of cool positions or moves consume him, he just played the game as just another middle blocker.
During the summer training camp, he practiced his blocks with Kuroo, Bokuto, Akaashi, and Lev, but didn’t really care to use that time to get better. But when the time came to use the skills he gained, he blocked Shiratorizawa’s spike and yelled the loudest and happiest he ever had during a game of volleyball. He had been told there would come a time where the game would mean something to him and he seemed to have witnessed it in other people, but this block was the closest he had been to truly understanding why volleyball was worth playing and why his friends were so obsessed.
Tadashi’s Bravery
Tadashi Yamaguchi has been friends with Tsukishima since middle school after Tsuki called Yamaguchi’s bullies lame. Yamaguchi wasn't quite sure if Tsuki meant to call him lame as well, but instead of asking, he looked up to the boy who stood up to bullies and wondered what kind of strength and bravery it took to be like that.
From that moment forward and especially during the training camp, when everyone but Tsuki was giving it their all, Yamaguchi noticed his best friend not living up to his true potential and he stood up to him by chasing him down after he heard him say that it wasn't worth his time. He used the bravery he saw in Tsuki to create his own, and it was the most wholesome moment in the series.