I usually read hackers manifesto. :)
Sit on my arse all day and chill. Do some epic mind expansion, magic mushroom type jazz and brainstorm malware functionality, determine its feasibility and if I'm capable of implementing it.
Or just, y'know, read a book on stuff I'm thinking about.
Back when it all started for me, it was because I was bored, so I decided to challenge myself. I'd say my main motivation is the challenge it presents. There's nothing quite like the feeling you get after solving a tough problem.
Read master OTW's articles.
I read Gibson, Asimov, Dick, etc.I listen to Industrial Music like Icon of Coil (somehow it motivates me to learn hacking).I read articles on securityweek or packetstorm to know what's up in the hacking world.And of course I browse NullByte, following tutorials and engaging in conversations with fellow aspiring White Hats.
My motivation when I started was that I realized how valuable knowledge is. And Hacking was something both requiring and providing a lot of knowledge. Also, as an IT guy, it was something I was interested in and something I could understand.
Watch Mr.Robot( a TV show). You can't do something more encouraging than this :p