Actually, you're really saying, "...has done a lot of things that have made my family angry." We just drop the second "has/have" to avoid unnecessary repetition. But both actions started some time in the past and have continued until now (and maybe into the future)--this is a textbook definition of the present perfect form. As long as there is no foreseeable ending to the actions by the cousin or the anger by the family, this is the correct tense.

As others said, present perfect has many uses, one of which is to describe actions that happened at a non specific time in the past. Maybe yesterday, maybe last week, maybe 10 years ago. The sentence doesn't say but we know these things happened in the past, so her family's reaction was also in the past. So the sentence is correct. Present perfect and simple past often go together like this, but it is also possible to combine present perfect and simple present or other tenses. For example: I've done things I regret. I've done things I'm not proud of. I've seen things you wouldn't believe. The difference in meaning is that you regret them NOW, you're not proud of them NOW, and you wouldn't believe them NOW.

April, Why use HAS DONE and MADE? The present perfect can be used to relate events that happened in the indefinite PAST to the PRESENT in order to make them important NOW. The present perfect allows English speakers to express some fairly subtle meanings. My cousin's decisions that MADE my family angry and disappointed with her in the past. You STILL respect her NOW for making her own decisions. How do you relate your continuing respect in the PRESENT moment for your cousin's decisions to the fact that her actions angered and disappointed your family in the PAST? You use the present perfect. *Although my cousin HAS DONE a lot of things that MADE my family angry and disappointed with her, I still respect her for making her own decisions. , By using the present perfect you, the writer, make the cousin's past actions alive and important in the present moment. This sentence has a much different emotional content than: Although my cousin DID a lot of things that MADE my family angry and disappointed with her, I still respect her for making her own decisions. It also has a different emotional content than: Although my cousin HAS DONE a lot of things that HAVE MADE my family angry and disappointed with her, I still respect her for making her own decisions.....In this version of your sentence the anger and disappointment of your family is also brought into the present moment. *In the original sentence the reader can assume that since you used the past simple verb MADE, the family is no longer angry and disappointed with your cousin, or if they are, that you consider the family's attitude as a PAST EVENT which, ALTHOUGH it affects you now, does not change the fact that you STILL respect her in the present moment.

In this case you use the same tense. This is because the family is immediately angry with your cousin. There is nothing in the sentence that says she does something and THEN they get angry. She just does things and they are angry because of it. Ultimately, the tenses should match.