The main factor for this effect is the amount of time spending with them. For instance, adults may be at the workplace for average 8 hours, that mean they would interact and collaborate with their colleaques half of the daytime. As a result, their relationship might be unconsiciously contributed and working with people who could cooporate effectively would arising our happiness level. Similarly to adults, schoolers may be impacted positively on emotions if they might on a relationship with some counterparts who share the same interest which students do not usually share with parents.
On the other hand, it is undeniable that family play a crucial role on our feelings. This is because they might always support our emotions and decisions. For example, if someone had financial problems or serious illnesses, family members would be on their side and willing to help them on some extent. As can be experienced, family could be more reliable than the others, that mean we would be happier when keeping a good relationship with them.
In conclusion, the idea that our relationships with work colleaques or classmates are as important to our happiness as our relationship with our family is not fictional but it is practical due to two mentioned reasons.