Depends on what I’m making and which ecosystem it will be a part of. For libraries, I use the MIT license most of the time, although I’m probably going to switch to Apache 2.0 for future stuff. It’s a bit more robust and has a helpful licensing framework.
When I make applications (and if possible), I tend to use (A)GPLv3. GPL sometimes doesn’t work though (for example, for my primary language, Clojure). I like the MPL 2.0 as a weak copyleft alternative.
However, recently, I’ve been reconsidering the whole open source/free software ideology, especially the focus on granting unconditional freedoms. I think the view that engineers shouldn’t care what is done with their work is outdated and irresponsible, and it applies to software devs as well. So I’m keeping an eye on the development of alternative source models such as ethical source or licenses like the Anti-Capitalist License.