The incongruity between occupations where the topic it's based upon is very stimulating, but the practical job is not, vs. jobs where the topic it's based upon is relatively unstimulating but the practical job is exciting.
I will use myself as an example...
In terms of subject matter, digital security is easily my favorite. It's complex, challenging, requires a vast array of understanding of dynamic interactions and creatively working within that infrastructure. However, the daily reality is that a career in digital security will usually mean sitting inside an office (likely one without windows) sitting all day in front of a computer monitor. You'll mostly be granting standard firewall access requests to non-threatening internal employees and not doing much of anything exciting. Despite how interesting and complex the subject matter is, the boredom can be unbearable and the hours drag by.
In terms of daily reality, welding is by far the most enjoyable of daily tasks. It involves a great demand of manual dexterity and concentration second only to surgery, as well as more power, superheated metal, and sparks than you can shake a stick at. Despite being dirty, hard on the body, and extremely repetitive, it's something I can do for hours on end and never feel bored. Yet, it's pretty simple subject-matter wise and not exactly an area of mental engagement.
So, what's worse? Daily dissatisfaction, or the type of dissatisfaction that kind of builds up over time, after which you get a taste of complexity and it's like all of a sudden you miss it dreadfully and wish your job had more of it?