For me, I have always been a lover of guitar music. As a teen in the mid 90's and living in Seattle, I had a front and center seat to the whole alternative/"grunge" scene. I can remember sitting in my room listening to bands like Alice in Chains, Smashing Pumpkins, Pearl Jam, Etc and thinking wow, this is awesome. Like many teens during that time I went out and bought a guitar at a pawn shop, an amp, and some guitar mags and taught myself to "play". I learned power chords and how to read tabs but i didn't REALLy learn to play. I could play simple stuff like "Come as you Are", "Today", "Come Down", and stuff. I also grew up hearing classic rock at my buddys house. His dad whould be in the garage for hours blasting Zep, the Doors, Stones, etc while wrenching on his bikes. So i had a taiste for the older stuff too.
I got out of playing for a while in my mid 20's, then picked back up again in my late 20's playing a lot or accoustic Folk and Irish stuff.
Recently, with the slow economy, I was out of work and sitting at my computer watching classic rockers on youtube. I though, you know what... I can do that! That lead me here to GT!
SO after all that comes my answer (sort of). Like Frankht, I have small successes every time I practice. When something clicks and I get a technique or riff I had been troubled with. I have made big success since I have started. I am more comfortable noodling around in different patterns,(let alone know the patterns) bends, double stops, slides etc. I can jam along with the jam station for a bit without getting lost. Soon I will have the success of getting timing down and not getting lost when when I play off, or in between beats.
My ultimate success is though, to be able to play the music I love. To her a song on the radio, think.hmm i think ill learn that one, and learn it. Also, to be able to put together some of my own music and even blend from all the genres I like, rock, blues, metal, trance, folk, accoustic. Maybe as a band, or maybe just at home in my own little studio.