Is It Back to Front or Front to Back?

The way i think about it is from a design perspective. I always want to start with, like, boll what's the goal state in terms of u x? And then starting with that as my constraints for how i'm going to develop the system. Then, if it's just me programming on it, let's say it leno again, side project or whatever, i will usually try to start with the part that i'm most afraid of not working. That could be anywhere. So quite often there's a performance thing, or i'm like, ok, in order for this to work in real time and not feel terrible, i need to be able to do this in this