Harvard study finds unhappiest jobs are the loneliest, with limited interaction and few opportunities to work with colleagues.Remote work during Covid-19 exacerbates loneliness, leading to job dissatisfaction and increased desire to quit.Tech, food delivery, and online retail services are affected by the loneliness factor, as employees often work in isolation.Customer service jobs are among the most stressful and lonely, with limited interaction and frequent interactions with angry and rude customers.