You wind up taking work that at the end of the day you’re not proud of and over time that will eat your soul.
Great talk by Jim Coudal about how they moving from client work to your own projects, or to put it another way:
You know that idea you have? Do it now. Not in 6 months. Don’t squeeze it in at the end of the day. Treat it like it’s a paying client: give it the resource it needs, meet the deadlines.
Also don’t worry about failing. Some of Jim’s (as it turned out) not-so-great ideas in this talk are wonderful.