I totally agree, noticable plastic surgery is a huge turn off for me too.
I personally enjoy the natural look, even if it is a bit less pleasent to look at. I'm kind of old fashioned in that way.
But there are cases where there is plastic surgery involved where I didn't notice at all and only found out waaay later. So, a counterquestion, if you liked the look of something and then found out it was altered through surgery, does it change your opinion on it ? It's weird for me, it shouldn't because I liked it before but it does do make it a bit less appealing.