I can think of few occasions where I said this:
1. I wasn't as attracted to him as wanted to be--he didn't look as good as brehs I've dated, but had a great personality, so I had conflicts on how to proceed with him.
2. He was different from guys I've dated, as far as his personality goes--he was more nerdy/corny then what I was used to so it was a bit of an adjustment.
3. He's someone I wouldn't have normally dated, but gave a chance to because there was something about him that intrigued me.
In every case, but the first one, it was actually a positive for me, because they were so different I was more intrigued/engaged with them-- they introduced me to some new things and experiences which I appreciated and grew to like about them.