All, that i'll say further - it's based on my personal experience, but i think millions of people have same opinion.
Too many years i've used photoshop as only image editing programm.
For that time i've learned it's interface.
When i made a try to use free paint.net i noticed, that "UI is not comfortable, as in PS". Of course it's a matter of habit, but...but...
I think user make a desision use\or not paint.net software in a first 60 seconds after starting the program. It decide yes\no.
The idea is - make UI as exact copy of PS. So in that way user will be like in it's own home and accept your software.
Or, to make configurable workspace like offers Gimposhop.
