One issue in particular that I ran into was the difficulty in context switching between my day job and my side job. I imagined being able to do an hour here or there before or after work. But in reality I found it really hard to get any meaningful work done in an hour, which meant I needed to allocate larger chunks of time than I originally planned. That meant I often ended up sacrificing entire evenings, or chunks of my weekend on my side job. The difficulty in context switching also caused me to procrastinate a lot, which also made me feel terrible about myself.