This graffiti is the effort of a n00b. By which I mean amateur.
Spray paint runs when you hold the can too close and spray too much on. What you should do is stand back a little, flick your wrist, and use little bursts of paint to build your tag gradually. Not that I condone this sort of behaviour in relation to public buildings or property, mind.
But anyway, now you know that dribbly bits = n00b. Go ahead, impress your friends. You don't have to credit me. Although obviously you should.