Fancying someone but no spark?

[Tickdurpin]

Apologies if I sound a little naive but I've heard people saying they found someone sexually attractive, got on well, had stuff in common, no major incompatibilities but there was just no spark? When I hear this, I kind of wonder what's missing?
Feelings take time to develop, I always thought the spark thing was just an excuse to say you didn't fancy the person.
I've honestly never had some Disney-style enormous spark with someone I met for the first time, I just got to know them and liked their personality, found them physically attractive and feelings developed over time.
Of am I just doing dating all wrong?

I think they mean they don't find them sexually attractive maybe

The spark, I think, is when that person makes you feel excited and alive. Butterflies in your stomach just thinking about spending time with them.
I’ve found some men attractive over the years, some interesting to talk to as well, but with DP there was such a sense of rightness even when we were just friends at the beginning. Years later the spark is still there.

I always think the spark refers when feelings of lust are reciprocated. So you both fancy each other then same.

I agree the spark is the passionate lust.
So my boyfriends were generally people I got to know and the more I knew the more attractive they became. My husband is someone I'd noticed at work but wouldn't say I fancied. He seemed nice though, and when he asked me for a drink I was happy to accept. The feelings and attraction grew as I learned more and liked more about him. Married 16 years now.
One particular boyfriend in my early 20s was all spark. As soon as we laid eyes on each other it was a lust "must have you" type thing. So much spark. When we broke up after a year I always maintained he should have been a fling and the spark is what made me think he should have been more. So yeah, spark is lust for me, not love. It's just pheromones!

I always thought the spark just meant the feeling of ‘cor i fancy you I’d like to go to bed with you, we get on really well’.
But then I met a man, didn’t occur to me I fancied him, and when he brushed against me in conversation I felt a full on SPARK 😁
A lightning bolt and I sure as hell fancied him after that, it was like a spark of realisation, totally bizarre. That said , a spark is not necessary to sustain a relationship / marriage, and I guess feeling a spark is no guarantee of anything more than that.

Once I hit 30 I stayed away from the sparks, they're overrated. They always led to crap men and crap relationships. I don't have a spark with dh and it's the best relationship I've ever had. Wonderful man, great father, best thing for me and wouldn't trade him for anything. I guess it's all about what's important to you as an individual. Im sure you'd find someone eventually that made you feel that way, but I don't think you're "missing out" on anything.