So I get this question a lot.
I didn't really choose Buddhism. I don't know why people choose Buddhism because Buddhism chose me.
When I was seventeen years old, after reading part of a book that only tangentially mentioned Buddhism, I meditated for the first time. I'm not even sure that the meditation 'technique' mentioned in the book was Buddhist per se. Heck, it was more of a description of what one meditator felt she was doing. Thinking back, it reminds me of shikantaza or what Adyashanti advocates.
A little background... I used to hang out in this about-to-be-condemned house that my friend's older brother Jason lived in. A bunch of the kids in the area hung out there and drank Keystone, SoCo, Kessler's, and Old Style. Sometimes we smoked pot.
Jason had borrowed this book from the library, and I, hanging out not drunk, not stoned, had picked it up and started reading it. This book had some sort of something to do with things 'Beyond the Occult' - OOB experiences, remembered reincarnation, the differences between Hindu and Buddhist meditation as relates to startle-ability (is that a word?) - that sort of thing. For reasons I don't understand and with such scanty understanding of what meditation was, I was inspired to try it. I sat in an old couch in a room off to the side during midday when the house was still relatively quiet and basically just did what the woman in the book described.
On the third try, I discovered some things that were quite surprising.
I couldn't find a 'me'. I found all sorts of references to an 'I' or a 'me', but it was like every story I had about 'me' had a footnote that said 'see this other thought/story', and then that reference led to some other story or reference which then referenced something else altogether...and on and on into infinity. This sounds like it's a disturbing revelation, but it's really not. I simply could not find a 'me'. In the end, I had no idea who or what the heck these stories were talking about. There was just this is-ness happening in each moment. Over and over and over.
At the same time, I also realized that I never experienced objects. There were only sensations, and even those fled from direct observation to the point that I couldn't even say they were anything. Everything I thought was real was ... well, real, but not what I thought it was.
There was more, but none of it as truly astounding as these two things. I felt profoundly stupid, but ecstatic at the same time. Why had I not noticed this before?? Why doesn't everyone notice? It's right fucking in front of us all the time.
Of course, because of the remoteness of where I grew up, it took two more years before I really learned about Zen, and I still struggled in the dark with my psychological issues. A minute with the lights on does not dispel all darkness, but it does dispel all doubts. It's been years since then; years when sometimes the lights came on at nearly full-strength, times when they were dim, and times when I couldn't see a damned thing.
Nonetheless, I have no doubts about the fundamental truth of Buddhism.