Recently, I had far more final tables than usual over the course of a month. 

I followed it with actually losing just as many buy-ins for a total wash.  Typical of my poker playing actually.

On the surface, someone might tell themselves, "You just have to stay disciplined with your play, and refine your strategy."

That's fine, but you should also have a strategy.  And, my strategy is wrong. 

I take chances when it's ill-advised, I reenter too many times, I rebuy too many times, and even after saying all of this is wrong, I STILL think I should do it. 

I feel like being too tight, and too conservative will have you barely making the money, and hardly ever winning. 

Being a little looser, and being willing to take chances may have losses, but the wins will be significant, and more often. 

I suspect it's somewhere in the middle of that coupled with some strong evaluation of my game, and just learning about the game more, in general. 

Having a better idea of what my range is by position, by stack, with X, or Y to my left, etc.  Having a better idea of how that range is doing against various opponents.  Having a better idea when it's okay to steal versus when it would be better to fold.  I could list fifty more things...the point is studying and thinking more about the game than I have been doing over the past 3-5 years. 

I've had hugely positive ROI in particular games, but overall, I am just not good at poker.  There is no way that I can be looked at as being good at this. 

It starts with my poor emotional control and lack of discipline, and ends with my incomplete knowledge of overall strategy.