Depends on several factors for me.
Not Annoyed:
- If it's cross-posted to a community that's not almost identical to the first. e.g. Crossposted from News to "Not the Onion"
- The community receiving the crosspost is small/niche
Mildly Annoyed:
- Cross-posting to a similar community, especially on the same instance. e.g. News -> World News.
Annoyed:
- If it's just someone posting the same thing to 2-5 communities at once. I find it highly obnoxious
- Someone doesn't check that the same article (or almost the exact same article) has been posted to the same community already (depends on the UI/app if that counts as a crosspost; in the one I use it is)
Extremely Annoyed
- The way Lemmy defines cross-posts under the hood. There's no direct link between them at all, and they're a completely artificial construct on the UI side. Basically any two or more posts with the same URL that come through in the same API fetch have to be rolled up by the UI. Some UIs will extend that to the title as well.