... are both just names for different kinds of ego adjustments, down or up. There are plenty of reasons to be humble and plenty of reasons to be proud of accomplishments too. You could probably tear yourself down pretty easily if you wanted, and yet you could also do the reverse just as easily. For example, I could think of about 50 people who are in better institutions than me, making more money, or more famous, etc... in my field, depending on how narrowly or broadly I defined it. Or 20 people who know more about Lorca or Gamoneda. On the other hand, I can point out that I can out-publish everyone in my department. That I've published in PMLA, Diacritics.
It's probably hard to avoid both kinds of mental activity. You might do one more than the other, but they are both forms of ego management, and I think most people do some of both almost every day. They can both be motivating, too. Nevertheless, the main focus should be on the "working ego," that is, the ego that gets things done and the immediate gratifications that come from actually working on stuff on a daily basis. In other words, past accomplishments are great to remember if you are otherwise having a bad day, and humility is motivating it you feel too complacent, but the real pleasures of ego are in the act of creation itself. In other words, in writing itself feeling good to you as you do it.