I once had a colleague put forward an unscheduled change in our application that affected 95% of our user base while I was on vacation. Awesome.
It was the addition of a required field to a critical piece of the application, along with a relabeling, per an individual user request. The field label was non-sensical and if I know the application and can't figure it out, there's no way most of the user base could.
One of the first emails in my Inbox when I got bacK? "What's a <insert field name> value? It's stopping me from submitting the form" Begin chaos.
This user request came from a group amounting to about 5% of the overall user base, and the user named the field. Did my colleague review the field name and think "Does this make sense? Can someone who never used the system understand this? Or can someone who actually does use the system understand this?!" Negative.
If you haven't figured it out yet, I was the Product Manager of the much larger user base (over 50%).
I'm not going to say I've never forgotten to think of every single user on the platform, but I will say that I always keep the greater user base in mind. Always try to step back and consult with your colleagues on any change affecting a large aspect of your user base, and do present the case for any change before implementing it if you see great downstream impact.
Something as simple as addition of a new required but mislabeled field to a payment form could frustrate users and lead to hundreds or thousands of lost sales due to a lack of useability and prior familiarity.
How do you handle colleagues going rogue and putting through changes for a small subset of users causing greater distress to the overall harmony of your user base?
Let me know in the comments!