Assuming you were both single.
Just out of curiosity.. let's say you have a friend of the opposite sex who you get on really well with and you also find them physically attractive.
What was it that stopped you wanting more?
I just find it all interesting..
Some people look for 'the spark', for me the spark basically means do I fancy them or not.
Honestly sounds immature but I couldn't be close friends with a man I find attractive, because I know I'll end up wanting more.