@wineisnecessary, I think having somebody in the office who is subjected to coercive control from a husband who obviously thinks a trip to the toilet is a cunning ploy to have a quick bunk up with a bloke from Accounts doesn't really count as being unprofessional - more being very obviously in need of somebody saying quietly (like the manager) that there is an employee assistance programme and that level of control/monitoring isn't a healthy relationship.
The one I hate the most is one I was guilty of for a short period - the dickhead partner that is always hanging round, waiting for her.
For fuck's sake, just leave the poor woman alone for nine hours a day - she doesn't want you here 'just passing' or 'thought I'd pick you up on the way home' when you're there an hour before her finish time, chatting to the receptionist trying to get information about the people she works with and details of her precise movements during the time she is not directly monitored and waiting to see whether she walks through the door smiling at a male colleague to be able to have a go at her about it later and accuse her of having an affair with him. And, of course, if she gets into trouble about it or loses her job, that's a result for him - he won't stop if she tells him work has a problem, as that'll be her lying to get time alone with the menfolk.
The other one I hate is unnecessary controls over who and how you communicate with others - where you get grief for going to speak to people in person, for example. Yes, an email or phone call is adequate when you genuinely can't leave your desk - but making the effort to find them, rather than expecting them to come to you all the time or essentially issuing orders from afar, is far better.
In the same way, it's shit to have disapproval of you stopping to speak to the site team/cleaners/reception/security briefly when you've finished work and they aren't hugely busy. Two minutes to acknowledge their existence and value. It's not difficult, weird or unreasonable - and everybody benefits in the long run.