I don't find what is easy to be boring. What's easy offers the possibility of making a game of it while accomplishing it, using my mind for other (more challenging thoughts/plans), and/or having plenty of time left over and/or on the side for other things. So, I don't really get bored when dealing with things that aren't particularly challenging.
Then there's the stuff that falls under the "difficult" category. To me, those things can be broken down into a) things that are complex and need to be broken down into simple components, b) things that will take substantial time, patience and work, c) things that are better described as "impossible", or at least "impossible at the moment", because of either factors that one must change first if they're not going to be impossible or else things that are plain, old, always going to be impossible because there is absolutely no way a person can make any changes in order to make accomplishing the thing at all even possible.
I'll use as an obvious example someone who has absolutely no sight (is blind) and wants to be a taxi driver. (Let's not get into the driver-less cars that are now starting to show up, although they wouldn't need drivers anyway....).
With the non-impossible-but-difficult-challenges motivation comes when/if a person can break things down into simple components and/or as a person addresses changes that are within his power (or at least deals with some components of the challenge while holding off, if necessary, on some changes he can't change at the moment).
I think if someone really wants to accomplish some things the motivation is always there, and if he only half-cares about it or doesn't care about it all that much (if at all) that's when motivation becomes an issue. Well, that and when the person has bigger (or different) concerns/things on his mind than the difficult challenge
For the most part, I'm motivated if I care/want something enough and if I'm not exhausted, don't have someone else moving the goal-posts and/or am able to keep those inclined to doing that far enough away from my own goal posts that they can't get at them to keep moving them. That, however, can be where making wise use of what is easy (and one's time) pays off later when the goal-post movers are eliminated (and/or when moving goal-posts caused by life-in-general, rather than other people, can be adjusted to).