Indeed, it's the key to pretty much everything. However, I know way too many people that do things they aren't dedicated to and therefor don't do them well. Dedication is quite a life changer (may it be temporary like in a little project or permanent like in a hobby). It's a verb like love is a verb as you aren't just being dedicated to something or you aren't just in love with someone, it takes work and you will have to sacrifice yourself to do so.
If I would have to answer the question for one particular case, I wouldn't know what to choose from so let me answer it for some: I got here, in magic, by watching David Copperfield and David Blaine on TV and being pretty sure I could do those things too. I got here, in music, by having an older sister who played the piano before I was born and got me to play it too. I got here, creating this community, because I was tired seeing forums humiliating their members. I got here, in the entertainment industry, because I live in a very stressful environment and I offer everyone to take a break from that stress for a little bit and feed myself from the delightful reactions it gives (yay for everyone being happeh!).