prone

The path of least resistance is where you'll find prone: it refers to whatever you're likely to do.

The Latin root of this word is pronare which means to bend forward, and it's a handy way to remember both meanings. If you tend to wait to start your term paper until the night before it's due, you are prone to procrastination — you bend toward it. If you stay up so late you fall asleep face down in the book, you are now prone at your desk.