What inspires you to really love a piece that you are working on? No idea. Sometimes a piece looks rad in my head and then looks crap when I draw it out, but sometimes it unexpectedly comes together and I love it. If it's pure lettering or calligraphy, then spacing is a big thing - if I can get the spacing right between letterforms, then I usually buzz off it.
Who influences you the most, art wise or not? Art-wise: Keith Haring, Ed Templeton, the french guy, Don Pendledon, Fos, Steven Harrington, Geoff McFetridge, Kevin Lyons, anyone with a skate or graf background or that paints bright bold, colourful characters or shapes. Lettering and type-wise: Ken Barber, Sergei Shapiro, Gemma O'Brien, Erik Marinovich, Kris Sowersby, David Milan... There's tons more than I can't think of right now - the internet is full of talented people!
More of Matts work on his site www.mattredway.com