I've been mapping since December of 2014, but before that I've always been a level designer in every other game I played. When I was younger, me and my friends would dedicate whole notebooks to draw pac man and Super Mario levels. I also loved creating mini games and giant builds using lot of red stone in Minecraft when I was younger. Here is my biggest creation I made during the summer of 2014 (and the video has my stupid voice in it :/)
View: https://m.youtube.com/watch?v=SN73RHLuXQs
I notice now that every single design of my maps are always sorta "gimmicky" and it seems that I always like to do stuff different. I like more creative, not done before, designs and ideas. They can often lead to failures (cp_camp) or success (pd_meme_machine). Specifically how did I start mapping? No offense to Crash or anything, but I feel his tutorials don't go into as much detail as they could due to them having the fast paced style. Also, they didn't exsist back when I started, so I always watched TopHattWaffle's tutorial series. Some of them are pretty long and go into a lot of detail, and it's all the technical stuff that I enjoy. I've watched this one like 20 times, some of them because I needed help, some of them because I just enjoyed all the technicality of them:
View: https://m.youtube.com/watch?v=swBfUW-Bsxs
Also when I made my first map, I didn't know what ABS was, and made all of my payload logic manually by following the VDC. I'm super glad I did that, because it helped me learn the I/O system very quickly and made me able to do stuff like pd_meme_machine without much help needed.
Though I really enjoy the mapping process, and before I got into mapping, I animated and made art (and I still do). My goal for my whole life is to entertain and make people happy, and to give them a new experience. I have an everlasting goal of getting a map into the game, but I'm not fueled by that. I'm fueled by knowing people will like something I make, or knowing people will be impressed with me.
TL;DR: I did level design before tf2. I like doing lots of hours of work and doing stuff manually, knowing people like my creations.