My primary workspace is a clean desk in a dedicated office at home. It is not a desk in the bedroom, or an office/spare-room/storage room, but an office. It has books on shelves, a printer on a pedestal, a filing cabinet, a white board, and a couple plants for a natural touch. There is no gaming device in here, so I cannot use the room for entertainment. It is easy to make the distinction that if I am in this room, I am doing work.
The next "workspace" isn't actually dedicated to work at all. It's the couch, in the living room. It's the same room I eat from, watch films, and play games - yet I still pull the laptop open and do some form of work here.
The next "workspace" varies on what the current job requires. It could be a client's office, a coffee shop, or a co-working space.
This difference in workspaces wasn't planned. All work used to be done via the office itself, however after naturally writing content from the lounge on a pleasant morning, I found it far easier to focus on the task from the living room. I could also tinker with designs, but could not affectively write code from here - the office room however has the complete flip of this in that it's very easy to focus on code but harder to focus on content.
Some of this feels like a lack of stagnation. Working in the same place all day, every day eventually bores my mind. The office could always do with a "quick tidy", which goes down the route of procrastination. This problem stopped the moment I separated workspaces to different tasks and it took no categorisation to do this - it happened without realising, other than regaining energy and focus in every task.
Both environments are very distinct - the living room feels more natural due to its decor. The window covers most of the south-facing wall which allows natural light to flood the room well into the afternoon. It feels very relaxed, very bright, and very easy to think with a more creative mindset. The office's decor and setup however give a more focused seating position and atmosphere if nothing else.
If you keep getting a mid-day slump, or generally feel bored or unenthusiastic despite doing the job you strived to get then it could just be as simple as a change of scenery for a couple hours a day. As long as it is a significant difference, and not another desk in the same room. A couch would work, or taking the laptop outside when the weather permits it.