Projects: serial or parallel?

Because I've finished the udacity course the other day, I'm now focused on learning Rust.

I'm into serializing project, there is a great podcast about it.

It's highly unlikely, that I like all my projects the same.

If I do them in parallel, I start giving all of them some time, but after some days and weeks, I lean towards fun, joy and convenience and mostly quit the not-so-enjoyable projects.

They sit around in the drawer and I feel bad about myself.

I am allowed to quit a project, but I don't allow myself to juggle between the projects.

The decision has to be conscious. Yes or No. No "when I feel like it.".