Hey! I know where you can get a good hh:mm display real cheap! (Just kidding).
I think all three of those above motivations are valid. I am totally into electronics, have been since I was a kid. I like to build things myself even if it means I spend more money than I could by buying a device. I also like to design my projects myself - usually while leaning towards the parts I have or know how to use. In those cases I welcome detailed discussions of electronic theory & practice. But sometimes, I just want some electronic functionality without all the fuss, and I want it now. In those cases I will be glad to just go buy something for as little as I can spend. Often times it is because I am already in the middle of half a dozen other projects that aren't getting done soon enough.
Given the above, sometimes I like discussing electronic design ideas, sometimes I like building things myself, and sometimes I just want to find something that might already suit my purposes, and usually that is when I can't seem to find a device that works like I want it to. Partly it is motivated by when I need or want to have it done.
I like (sarcastically) the discussions that go something like this:
1: I want to build an amplifier, can somebody help me?
2: Sure, what kind of amplifier?
1: An audio amplifier.
2: What is your purpose? A phono preamp? Power amp? Stereo amp?
1: A lapel microphone.
2: So you want to make a pre-amp. Where will the signal go, to a recorder or speakers?
1: I have some speakers I'd like to use.
2: Is it battery powered or A/C.
1: I dunno.
2: You will need to decide, because often the design requirements are different.
1: Both I guess.
2: Well how big or powerful are the speakers? How much volume do you need?
1: The speakers are about normal size I suppose. I have two of them. I want it to be loud enough to hear well.
2: Of course you want to hear it, but do you need to fill a large room full of people or just a small room with a few people.
...and so on. It soon becomes obvious this guy has no clear idea what he wants, and no real experience with that type of equipment.
Often I would start to get into his level of understanding and generally find out he doesn't really know the difference between amps and volts. I can respect anybody reaching out for help to learn things, but sometimes it is just beyond writing a few paragraphs on a forum. Once I met a guy that wanted to learn everything he could, but when I suggested some books or even videos, he admitted he didn't like to read or watch stuff because he doesn't learn that way. It sounded like he wanted me to become his private tutor - well beyond my available time or ability.
** Please understand that I am not referring to anybody on this site. You guys seem to all be pretty darn savvy with electronics and engineering. **
But this has happened to me from time to time on other sites or even "live" in discussions with people I've met.
I play instruments too, keys and drums. Often times I meet people who say they would love to play, but when we really dig down into it - they don't want to practice, they just want to be able to play. I really don't know how that can be done!
Alright, I'll stop rambling on now. Gotta' take down the Christmas tree.