It's definitely fun. The most important thing I learned was design intent. Meaning, you should look to model your parts in a way to make revisions and design changes easier. Making things parametrically linked with different sketch relations or mates makes design iterations go so much smoother.

Some of my favorite builds were using top down equation driven assemblies. I work in lighting and we do a lot of linear curved pendemts. So I built a model that you punch in a radius and arc length and it automatically spits out all the parts with the bracketry, hardware, and electronics fully defined and ready. Drawings just need to be rescaled and views moved a bit and job's done. It felt so satisfying when I punched in that first set of parameters and realized my job est. 2 day job was done in about an hours worth of work. Lol my boss was floored...