Start learning category theory
Perhaps due to my rather small brain (literally), I dislike remembering tedious details. When in elementary school, I hated reciting classic Chinese poems, but liked composing my own :-). In high school, I hated chemistry but loved physics, because one could do everything based on a few principles in physics, whereas chemistry was all about memorization. Last year, I was chatting with a colleage of mine who had a Ph.D. degree in chemistry from Harvard. He said he's good at it because he could find patterns in all the tedious details and summerized them in his own head, so he didn't have to remember them all. So I said why not write those patterns down so others can benefit, and he didn't seem to like that idea. Anyway, let's go back to the main topic.
I did not do very well in math classes in China, perhaps because Chinese math education focused too much on problem solving techniques, which were basically a matter of remembering all the test coping tricks. But I do like math, because I find it elegant and profound. A mathematical understanding of the world seems always the most economical one. So I want to learn more.
To consistently apply my preferred model of starting from the most fundamental ideas, I decide to learn category theory. It might sound strange as even many professional mathematicians consider this branch of mathematics "abstract nonsense", but I think it might fit my aptitude. Who knows. In any case, I am following John Baez's book recommendation as a guide, and will be updating my progress here from time to time, when I have something interesting to write about.
UPDATE: Baez, among others, said they benefited from Goldbatt's book, which I myself find very readable as well. However, this MacLarty's article convinced me that Goldbatt's book might give the wrong idea about category theory. So I will stick with Lawvere's books.