Yes, I think you need both pull and push, the ratio depending on the situation at hand.
A senior sysadmin once told me that he asked all incoming recruits about what this proportion generally should be. The answer: 1/6 (16.6%) push and 5/6 pull (83.3%). I found that answer slightly amusing as it seemed overly general. On the other hand, he felt very strongly about that point and was quite annoyed with juniors' natural inclination to use push by default when pull could practically be used.
A senior sysadmin once told me that he asked all incoming recruits about what this proportion generally should be. The answer: 1/6 (16.6%) push and 5/6 pull (83.3%). I found that answer slightly amusing as it seemed overly general. On the other hand, he felt very strongly about that point and was quite annoyed with juniors' natural inclination to use push by default when pull could practically be used.