Yes, every machine is different as Rodney said.
I struggled with the 1/4 inch for years. I finally wrote down where I had to put the needle to get a 1/4 inch. Then I finally got better at my "art" and realized that it all wasn't me. My machine was finally sent back to the factory for and "overhaul." I got new feed dogs, new needle threader, you-name-it, I got it new. Can't tell you what a difference it made.
If you think you are crazy for not being able to get the 1/4 inch (and in my case a straight line; mine was straight but diagonal), consider that it just may be your machine.