Sewing stuff we are (unreasonably) anxious about

I'm currently working on my first swimsuit in proper swimsuit spandex fabric, and I’m really comfortable and enjoying the process. But it’s after 9 p.m., so I just stopped and now I am wondering, when did I get comfortable doing stretchy fabric?

I’m an intermediate sewist. I learned sewing from my mother and grandmother when I was a child, and until adulthood, I was really, really scared about anything stretchy because they always told me, "Oh no, stretchy things— that’s really messed up." Later, I found out a lot about technique—about the importance of proper needles, proper stitches, walking foot, straight stitch foot, elastic thread, and such. And right now, I really enjoy working with various stretchy fabrics (except stretchy velvety fabrics, I hate those :P ).

The thing that helped me most, I think, is that I started sewing jersey shirts for my kids. They were really small projects, so I wasn’t afraid of any waste of fabric. They were easy to manipulate because they were small, and I gained a lot of confidence and technique on those small patterns.

Also, don’t let me start on zippers—I was scared to death of doing anything with zippers for a long, long time. And I found that with a proper presser foot and a mostly after few really good tutorials, they aren’t scary at all.

I’m wondering, what are some aspects of sewing—like fabrics, techniques, or garments—that you were unreasonably scared or anxious about when you were a beginner or maybe you’re even still anxious about them now? And what were the tricks and tips that helped you to go over it?