right back at you lurking.
Yes perhaps you would be mightily hacked off. But people considering requests have to take a wider view than whether one person will be hacked off.
Take a team of 5 people, working hard, putting in the effort, good morale, working well together. Contracted hours technically say 9-5 with an hour for lunch, but like most senior/management positions, those hours aren't really realistic, and most people come in around 8.30 and leave about 6, either grabbing a sandwich at their desk or popping out for half an hour. Nothing excessive in my view. So instead of the basic 35 hours a week they are probably all doing about 45.
All working happily but then suddenly one of the team decides they are going to work to rule, only do their 35 hours a week, reducing their hours by 20-25%, and deciding they are going to 'compress' those hours. They are planning to work more or less the same hours as previously Monday -Thursday, so the same as everyone else, but on Friday they want a day off every week. And they want to get paid the same as before and the same as everyone else.
If you put in that request you may be mightily hacked off when it's refused, but the rest of the team would be even more hacked off that you were getting a free paid day off a week. Resentment, lowered morale, reduced productivity, loss of team spirit, it goes on. Perhaps they all decide because they are hacked off they will also only work 35 hours a week, and start showing up at 8.59, then not answering their phone if it rings at 5.01.
Call me old fashioned if you like, but I personally think a reduction in hours should usually be accompanied by an appropriate reduction in pay. If the person making the request acknowledges that if they want to work the same hours 4 days a week and have the 5th day off, that means a pay reduction, then everyone's happy.
One could also argue that if a job can be perfectly easily done in 4 days a week then it isn't a 'full time' job anyway. But that's a different argument.