[marta_morena_25]

This is common misconception of students or perhaps research people, who don't need to actually earn money with their projects.

Software needs to be as reliable as it needs to be to satisfy customers and not erode customer trust. And that's it.

Now sure, you can proof everything mathematically and ship your fitbit application within 10 years instead of 10 days, but there are more than a few problems with this approach:

1. You will be bankrupt before you even proved the first theorem

1. Your proofs will turn out to not align with realities of a real world environment

1. Hardware has bugs

1. Software you depend on has bugs

1. Requirements change like a flag in the wind, i.e. 100 times faster than you can prove your little theorems

1. Customers don't give a shit if your fitbit app is never crashing and always does what you think it should do. Especially if its 10 years outdated and doesn't do what customers want lol.