I find it interesting to listen to the introductions that different seminar speakers get. Sometimes the introduction tells you more about the host than the speaker.
Introductions I don't like may include:
"Sarah has published lots of Nature and Science papers."
Mention of the h-index or number of citations.
Mention of amounts of grant money.
"John has done important work in quantum biology".
"The speaker needs no introduction (so I won't give one)".
I have heard this many times but I did not really know the speaker.
A live dialogue between the host and speaker about the details. e.g., "When did you get your Ph.D with me? So how long have you been at Sydney now?"
"When I Googled him this is what I found out ...."
Recitation from an old university web page. For a few years I sometimes got introduced as someone who does research on the "electrical conductivity of DNA". I finally discovered that this was because if you Googled me the first hit was an old university web page that listed this. I worked on this for a few months before I discovered all the experiments were duds. I eventually got the old page removed and have not had this introduction since.
Glowing accounts of how great the speaker is, when he is a charlatan or mediocre. This either reflects hypocrisy or poor judgement on the part of the host.
Introductions I do like include:
A very brief career history.
A very brief statement of what scientific contribution the speaker is best known for.
Any personal connection between the host and the speaker. e.g. "We were postdocs together at Rice University".