There are plenty of people that “act out” and they do so for a variety of reasons, such as for the attention, or as a general need to have acknowledged that they are valued, and thereby worth the time of somebody to pay some mind to them, as well as to get basic confirmation from those that they congregate with that they are still considered to be a member in good standing within their particular group. In truth, almost all of us, need to feel that we belong to someone or to some group, and many of us that feel that way, will act out, at least from time-to-time when we feel that we are being consistently ignored, or marginalized. Therefore, this so signifies, that in those situations in which a given person, is not getting the attention that they need or that they crave from that of which they expect to receive some attention from, that they will thus become susceptible to looking outside their own people or group to someone or something else to get such, and that is probably seldom a real good thing.
So then, for a certainty, those that act out and seek attention, but don't seem to receive in response the corresponding reaction so desired, or the attention so craved; are going to find that someone else that provides for them that attention, for good or for bad reasons, is probably going to appeal to them. That, in a nutshell, is the fundamental problem, so seen, when we consistently fail to validate people that need our undivided attention. After all, we are social creatures, that need to feel valued, and especially to feel valued by those that make up our social group.
Additionally, there are plenty of people that do get a reasonable amount of attention, all things considered, when we account for the fact that people have responsibilities and duties that may well necessitate spending appreciable time and energy away from the group, in order to take care of work, school, and other meaningful things of that sort. So then, those people that continue to act out, are probably doing so, not so much because they really aren't getting attention at all, but rather as a way and means to manipulate others for their benefit, so as to receive the attention, that makes them feel valued or satisfied.
That said, though, those that crave attention aren't always necessarily high-maintenance, for some of those people when they do get the attention that they so richly desire from someone that they highly value, are thereby subsequently pleased to be compliant to the requests and desires of that person who is now paying attention to them, because having seen their personal value, validated, they are thus far more amendable to accommodate that person who has shown interest in them. So, to a certain extent, some of those that act out, are more than willing, to do to their quid pro quo part in return for having received that attention by thus conforming to the expectations that the other party so desires, thereby providing to all involved, a happy medium.