True..practice brings about greater perfection :)
I remember being trained to write in a flowery manner all through high school. Then in university it was a mixture of impactful writing and impressive words..
But once I did my first branding internship out in the real world, my writing style got cleaned up really quickly by my boss.. That was my first realisation that I had to unlearn most of what I'd practiced in school and relearn effective writing skills :)
the above video of Scott Adams will probably be a lot closer what your boss said then what you learned at school...