Honestly one of the most stressful things about tech is feeling like you have to "keep up".

So when I have time to toy around, its with something dumb or old. Or its more of a foundational thing/idea that lasts. Dumb things like 'how does a relational DB work' or 'how does bumpy work'.

At my day job, it feels like I always have to push the envelope. Its fun to just relax and fill in the gaps in my knowledge.