To be frank - what amazes me is the assumptions being made. My wife works in a big department at our local hospital. She is quiet and hardworking, having swapped a pressure filled banking job for one where she is low in grade with little responsibility. The description posted three pages back of how the department is run is very similar. However, now they have an influx of younger people who DO chat, laugh, messy round and take the job less seriously. Productivity has gone down, staff outings in the evenings have increased and next day absenteeism increased to match it. More people are happy and smiling. Bosses unhappy because staffing has had to go up to cover the workload.
As a new manager in a business area, you want things to be your way, but often, their historical way of working is an evolution that works for them, with that staff. Tamper and tinker at your risk. Older workers may just not wish to have fun at work.
My business is hectic in two periods of the year, my most lucrative role being managing 30 people working for me, and controlling hordes of others who work for a venue, and are there to support what we do. Every single place is different, and there is no point whatsoever trying to instigate processes they will fight against, and remove as soon as I go. They resent that kind of management. I develop what I do to give them the easiest ride I can, subject to what I MUST have. Rather than be seen as a 'manager', I volunteer for things that maybe few of them enjoy. If something bad happens, then I might be the person who finds the mop and bucket and clears the sick up - which is not my job, but taking somebody off their job to do it when I could do it and leave them doing what they are good at means I get incredible respect - for taking a suit off and turning up with steel toe caps on to help when they are really short. Years ago, I did this kind of work, so it's no big deal. Seeing me remain calm, and sorting things like this out means when I need things, I get them, without putting my boss hat on.
In my slack time, I still do some school supply teaching, as my ancient qualifications still count. You can walk into some school staff rooms and there is NO talking - everyone sits with one empty seat between them, and nobody says hello, or even makes eye contact. Other schools have noisy and wild staff rooms. Is it my job to start telling jokes and trying to get them to interact? Course not.
If you have a team who are quiet, perhaps sullen and uninterested in socialising, then sit back, and make gentle progress and respect their preferred working style. Walking into a new job and starting change puts their brakes on, perhaps covertly, and creates resentment about the new guy.
This is basic management stuff in the real world. I got told the other day I'm the most chilled out company manager this person had ever worked with - nothing phases me and I never lose my temper and I'm very supportive. None of this is true, but if they think it, then I've done my job - because behind the scenes I'm like an olympic synchronised swimmer - thrashing around under the water, but serene on the surface. Reading the OPs other posts, he expects sooooo much, and wants things to be done his way, and if they are done differently, isn't willing to wait and investigate behind the scenes.
It's, I suspect, just experience that is missing. I n' work out how old he is, or how experienced he actually is - but asking these questions on a forum suggests an unfamiliarity with management in real life. This comes with experience, and if you have the experience, you respond to forum questions, not ask them. You perceive a problem. Maybe they don't like each other. Maybe they just want to do their job? That's it!