Cloudscape

Do not be afraid to be content, even though you dream of more, but always keep dreaming even when you are content, and keep being content even when you dream of more; so that your thankfulness, and so your happiness, might help to make your dreams come true, and that your dreams might also help to make you happy.
Day and night must alternate within you; but so too, in some part they must be one. When night falls, keep the light of day within you, and when dawn comes, keep the dreams of night within you.

If you deeply aspire to achieve something, then by all means do all that is in your ability to achieve it, but remind yourself that you can do no more than just that. When you are already doing your best, you should not try to push yourself further, for it will not work, on the contrary, it will then only demotivate you. When you have reached the limits of your abilities, accept them as long as they are there, until you manage to push them further.
When you are already working hard to achieve your dreams, it is time to once more avert your focus from those dreams and turn it back on your experience. In this way, not only will it become more pleasant to work to achieve them, but you will also become better at it because you do so with more focus.
In this way, one can have very high goals without being pained by them. Whatever efforts you exert to achieve your goals, you must always do so step by step, departing from where you are to then arrive as close as you can get to your goal; if you have made up your mind what your goal is, it is no use of thinking about that goal when you are already doing everything to move closer towards it; instead, focus on how you move closer towards it and that alone. Devote yourself to what you do now, not to thinking of what you cannot do yet.

In the meantime, as you work to achieve your goals, enjoy what you have achieved so far and what you are achieving as you work. In this way, a compromise can be made between the need of achievement and a need of happiness without compromising either of both, and indeed actually improving both; similarly, such there are for all things.

Some people say technology takes away all challenges in life; yet we have never had more challenges than we have today. We have more to strive for simply because we have more possibilities. Many goals have been achieved, but for every goal we achieved many others became unlocked. So it will continue.
There is always something to fight for; even when he have achieved what we've fought for, there is something else, something beyond even that. In the end, there are no limits, thus we can push our own limits further and further forever. Even when we have achieved everything we could achieve today, with those things we will have achieved then, we will be able to achieve far greater things, and many of these will take far more effort than we are willing to sustain today.