I recently finished my PhD in pure mathematics. I'm not currently using it because I made an abrupt and idiotic career switch into something I didn't completely

I recently finished my PhD in pure mathematics. I'm not currently using it because I made an abrupt and idiotic career switch into something I didn't completely understand, but that's another story. Your level of focus and motivation is going to be dependent on whether or not you love what you study. Earning my PhD required plenty of long hours with boring problems, boring subjects, and awfully boring theorems. It was emotionally challenging to push around a pencil on problems I hated. It frequently seemed like a complete waste of time, life, effort, etc.. It required a level of focus and dedication that was only possible because I love my subject in the sort of way that keeps me up all night and ignites me with Christmas-Eve-Santa-is-Coming excitement in the morning. Sometimes it's easy to forget why you love your subject. Sometimes I despised mathematics. Earning a PhD helped me to move beyond these times, concentrate my effort, and make effective project management decisions. These experiences taught me a repeatable process for quickly mastering anything: Concentrate on the elementary, challenge everything, do the grunt work (yes, even when it sucks), and never stop thinking. Here is the best that I can offer you. I've been considering earning another PhD, but I cannot see the point. Earning my first PhD taught me how to master something. I can now do that on my own.