While working on a new Blender scene, all of a sudden, I notice Extrude isn’t behaving as it should. I wanted to Extrude, right-click, and Scale, but it didn’t extrude at all and just scaled. I knew it had to be a setting I forgot about somewhere… and that was indeed the case. Proportional Editing was still turned on. Gah! Luckily I figured it out within 5 minutes, but I wanted to make a note about this just in case anyone else is having a sudden problem with Blender not extruding properly, and this might be something you need to keep in mind. :-)
So, to sum it up: When Blender doesn’t extrude properly, check if Proportional Editing is turned on.
Thank you for checking out my Blender Note! I am by all means a beginner in Blender, so I do not feel qualified to label this post as a 'tip' or 'tutorial'. However, I decided to upload this note for myself, and hopefully it can be useful to others as well.