I think that 'To be or not to be.', is actually not the question or at least not the right one. This famous quote is something that goes against human nature.
For the religious; If we believe that God made us all in his own image and as such that we are all unique and capable of astounding things, then, to simply categorise oneself is only but an insult to the divine being. For the agnostic; if our existence is by chance or a product of a series of steps in the form of a evolutionary cycles, then, is it not a waste to limit yourself to a single track?
The question instead, perhaps, should be 'To do or not to do'? Most people, in their uniqueness, want to do a million things as they should. To ask oneself the question of: 'To do or not to do' is, by far, simpler and in most cases, even rewarding. Perhaps, in most cases it is also fairly entertaining. The scale of the consequences related to the latter question is not as daunting as that of the former.
The question 'To be or not to be' implies that one is restricted to two options which on its own has the profound, yet detrimental, effect of binding a person's thought within limits. Limited perception is unhealthy as it is and surely, we can all agree that a bird in the wild is merrier than the one that is caged (or is it?).
In order to be something or someone, one's goal is to become. In the pursuit of this goal, one spends a lifetime to achieve it and then probably becomes their becoming, whatever it may be. However, by that time they have spent years upon years of the only life given to them. Some people are satisfied with that achievement but most want to do more or perhaps something different. This may be the reason why a lot of people think that one lifetime is just not enough for them.
Society, as it stands, works as such that it has already branded a specialised person as an engineer, a teacher or a doctor of sort. The tight rope, i.e. the neo-society and it's infrastructure, is not flexible enough to fully accommodate diversity and therefore unwillingly punishes tangents. Considering this, one might begin to comprehend the charm of the question 'To do or not to do'.
Leonardo di ser Piero da Vinci, or Da Vinci as he is famously known, did music, mathematics, science, painting and so much more. He accomplished all this by choosing to do instead of choosing to be.
To one, of the curious inclination, it would seem rather bizarre that such diversity, or at least it's visibility is becoming a rarity. It is wonder worthy why that is the case. Perhaps, it is because our society has devolved in such a way or is it simply because the world has become the super store of mass produced Aristotles and Da Vincis such that no one really stands out.
The fact is that, as humans, we need all of our senses to be stimulated for the purpose of complete nourishment of our mind, body and soul. Imagine from a parental point of view, if one were to ask their children to make a list of things they wanted to do in life or in general instead of what they wanted to be when they grow up. The latter approach, implicitly, imposes bounds which the child may subconsciously acknowledge and therefore accept over a period of time. Instead, imagine using the same technique to plant ideas by asking what they would want to do for work, which musical instrument they would like to learn, would they like to write and other questions along those lines. By posing options as such, a parent would now be saying to their child: 'You can choose to learn as much as you want. There are no bounds.'.
One must realise that the options are limitless, that the boundaries are non existent and the experiences aplenty. One must realise that the intelligence is relative and that the perspectives are diverse. For any number of people that will disapprove of what you do there will be at least as many people who will understand and support it. The so called Yin Yang principle and keeping everything in balance is key.
Without a doubt, the idle mind can be the devil's playground but a one track mind is it's abode.