When you look at a software engineer's code you can tell a lot about the engineer, the skill level, the frame of mind of the person at the time and the person's logic towards problem-solving.
Devs have good code days and bad code days, it'll be too optimistic to assume that everyone goes to work everyday in high spirits. On some days work pressure or an emergency demand at work can make a software engineer abandon conventional rules of thumb in order to deliver a solution as soon as possible. Code reviews are very important in improving the quality of code.
It is advised that software engineers be given ample time to produce solutions however the reality doesn't always abide by this. This is why frameworks and other tools are becoming rather essential to devs who want a quick fix depending on the urgency of the situation.