From this 30-something single….
It could be how you approach it. As oomis says, some shadchanim push an idea, even if you keep saying it’s not for you. I have been redt to someone over 30 years my senior! When I thanked the person for thinking of me but said that I was looking for someone a little closer to my age, I was told that I need to stop being so picky. The shadchan told me to think about it and call back. I didn’t call back on that occasion. (I thought that the fact that he was older than my father was not being picky.)
Another time, it was someone who I knew (the brother of a high school friend). I know of some serious issues he has (I saw him punch his mother in the face when I was visiting his sister!). The shadchan would not take no for an answer. He then called my mother and complained that I was turning down “a gem.” My mother had no idea of the conversation we’d just had (and of the details of my friend’s brother–she knows my friend and thinks she’s a wonderful person) and called me right away very upset that I had said no. I didn’t want to tell her all the details, but she finally accepted that I knew things about him from spending time at my friend’s house. But the shadchan kept on calling me, so I finally stopped returning the calls.
I thank everyone who thinks of someone, but I especially thank those who have some rationale behind setting me up (rather than “they’re both single, so it’ll be perfect!”). And if I have a good reason for saying thanks but no thanks, please respect that.