I had a similar experience, but after I eventually figured it out, I grew to appreciate the insert key. Mostly because there were a few times when someone else was getting frustrated with the same problem and I was able to help them. It made me feel powerful; I had suffered, but I now possessed the knowledge to save others from the same fate.

Two things

1. Overwriting existing text
2. Some legacy scheduling software I use at work, where ctrl+ins inserts the copied day for a given coworker. Useful if you need to swap days in the schedule and a coworker has 3 different classes in as many rooms, and in some classes there are students from multiple courses. It's archaic, but it saves time.

For entering overwrite text mode?