Here's a question to both pg and rokhayakebe: How do you each define "working hard"? Is it the difficulty of the problem you're trying to solve or is it more

Here's a question to both pg and rokhayakebe: How do you each define "working hard"? Is it the difficulty of the problem you're trying to solve or is it more so the time spent thinking about and/or physically solving the problem? I ask this because I often find that at my job, the work is more frustrating than hard. Yet, at the end of the work day, I still feel drained physically and mentally, although the work is not challenging (or satisfying).