Every morning I see hundreds of commuters faced with a decision like the one above. I am pretty sure none of them think about it in any great detail. It is probably an intuitive reflex action to take the "user-created" path on the left than the "system-created" path on the right. The path on the left leads to the end goal (crossing the road) much faster than the path on the right.
This situation illustrates a situation that anyone who builds or sells a product could potentially face. The product that you built may not be used in the way you intended it to be used. Even more likely is that your users might suggest a better way of solving the problem you set out to help them solve!
Some companies are better than others at doing something with this feedback. The rapidly expanding Chinese device company Xiaomi have an obsessive and rapidly-executed focus on user feedback. Product managers at the company can spend half their time perusing the company’s active user forums. A number of unique features that they have built into their products are in fact user suggestions. These innovations came from a users head rather than from a product manger. This makes sense as the average user would likely have a lot of feedback and improvements to share after using the phone extensively.
Another great example I saw from a non-tech company (I love non-tech examples as I spend my entire day looking at tech) is from Coca-Cola Vietnam. They noticed that people used coke bottles for other uses after they had finished drinking. In order to incentivise this recycling, they helped this reuse to occur as the video below shows.
I had an example recently where a product my team sells was being used by a partner in a way that it was not "supposed" to be used in. This use case did however solve a problem that the partner was trying to solve. While my first instinct might have been to say "umm you are not supposed to use it like that" I decided not to say anything immediately. After some reflection I realised that a better thing to say would be "umm that is great - would you mind sharing this with Partner X as they are trying to solve the same problem as you?"
So next time your user doesn't behave the way you thought they might, I encourage you to observe what they are doing and validate whether their way of solving their problem is better than the solution you gave them to try and solve it. Good luck and happy observing!