Kaitlyn C. answered 4d
Flat Patterning, Couture Sewing, fitting, and more from Draper/Tailor
Short answer, yes, sewing on the bias is incredibly difficult when you first begin doing it.
The longer answer is that sewing is a skill and the more that you practice, and learn how different textiles behave, the easier it gets.
If you're new to sewing bias-grain garments lightweight and "slippery" fabrics, such as satin, will be difficult to pin, serge, feed through your machine, and press at the iron without stretching. However, heavier and rougher textiles - like plain-weave cotton - will be much easier to sew on the bias. These easier fabrics often come at a cost though, as bias garments rely heavily on the lightweight nature of certain textiles to beautifully hug the body and fall towards the floor.
In order to successfully pattern, cut, and sew a bias garment it does, unfortunately, require a vast understanding of fabric-specific behavior.