Honestly I felt like that at first too. I always felt like "if i put THIS HERE, then itll have to be PERFECT and stay that way".
But i sort of learned that w/e u design/terraform/etc doesnt needa be perfect. I mean just DO and CREATE what u want. Then later u can expand on it and improve it later. Or maybe it grows on u and u like it the way it is.
EX: Want a farmers market but cant decide how to do it? JUST MAKE ONE. make all the items, play with placement, etc. Then keep it that way for a bit. And let it sink in. Try to see how u want to improve it later. But don't think u needa do it all at once. Or make it perfect the first time.
All Im saying is, don't expect every area of ur island to be finished ASAP or perfect the first time. (or even 2nd, 3rd 4th, etc). Cause I used to think that way and it drove me crazy. Now I just do my town how I want and when I get new inspiration, I just mix things up.
Trust me, its much more enjoyable just adding what u want rather than focusing on "ITS NOT DESIGNED GOOD ENOUGH".