When I saw your question, I straight away saw it from my perspective. I have been nursing throughout my career, either as a staff nurse, ward sister, specialist nurse which then was advanced to (advanced) nurse practitioner. When I was in this role, I was funded to do my PhD and thn have been writing a lot of articles for publicaton (until 2017). So, my life has been very fulfilled and this has been through increasing my knowledge. Now I have been retired since 2012, I still enjoy increasing my knowledge. I am reading a book about evolution and still love ResearchGate. I don't do Facebook; just RG! And learn a lot from other RG researchers about different things to what my specialisation was in nursing; bladder and bowel problems.
Sorry to have written such a lot here, but yes! Knowledge makes me happy. My husband is similar. A lovely question.