You can’t expect chemistry or to “click” on the very first or maybe second date. If you do, that is great, but some times it takes a little more time to warm up and really be yourselves when dating. Many young people are so burnt by the dating game that they are guarded, some are just plain nervous, so young people have to be patient. My rule is if there is no reason NOT to continue then keep going and give it a chance to develop.
If someone says “we didn’t click” or “there wasn’t any chemistry” after one or two dates, he either didn’t want to go out with her to begin with, or he already has his eye on the next one on the list. He obviously was not willing to give her his full attention and the opportunity to see if she was a possibility. If he couldn’t give more of an evaluation such as “she is way too shy, she is sloppy, she doesn’t dress well, her laugh is annoying, she is argumentative, she couldn’t hold up her end of the conversation, etc.” then he just wasn’t willing to give her a chance.