Ok, this might get backlash as it's a very commonly posted answer on here where workplace issues are discussed. Would appreciate constructive comment instead of abuse if you don't agree
It really bugs me when someone posts about a problem they have with something at their work and the answer is 'you should log this with HR', 'you should speak to HR', 'have you got an HR department'.
We're in 2019, HR isn't a 'personnel' department anymore that deals with peoples moans and issues. Yes, they can advise on policy, but why should they deal with every single workplace issue! That is what your line manager is for. People need more progressive views on what the HR department does and this is why they have a bad rep in most workplaces.
Granted, there are probably lots of companies where HR deal with all the nitshit. But the best companies I've worked for are large, modern ones that make the line manager have accountability to deal with difficult conversations and situations. Not for employees to come to them and tell them someone in their team didn't invite them on the work night out.