Grateful to know I can make a man feel this way and that I had this little connection via /r/gratitude

I'm 29 and very inexperienced in love and romance, rarely like anyone and vice versa. I'm not unattractive or a bad person or anything, but this whole love-thing never really works out for me. I'm simply not a girl men tend to fall for. I'm used to it though, and I'm picky anyway. I live my life independently, date here and there but this belief that men are never really into me is something that to me seemed like a fact. Recently something that gave me hope was over before it started and instead of being sad I'm gonna be grateful.

More than a year ago someone came into my life in a semi professional context (don't want to give away too much but one of us was at work, but it's not a customer facing thing or anything. Anyway) we instantly had a little chemistry going on. I couldn't really believe it and my avoidant tendencies immediately activated. I would convince myself it was in my head, or that he knew I liked him and he was playing into it for fun. Just a lot of overthinking and wrong conclusions. I'd retreat a little and so would he. Then we would warm up again. Anyway. He was always incredible thoughtful and had the sweetest smile. My friend who met him too the first day said he had only eyes for me even then. We didn't get to speak very often but when we did he would be *so* nervous, stutter, sometimes get flustered or scramble. He always looked at me with a glimmer in his eyes. His eyes would always find me. He's 31 but would turn into a little schoolboy before my eyes if we talked, sometimes unable to properly speak, sometimes acting too cool (when this happened I'd convince myself again he hated me). In one of our last interactions he gave me something for free (I needed it and it wasn't free, so it was a favour), I thanked him by giving him something small in return (this was huge for me) later on and his reaction was so overjoyed (in bodylanguage, genuinely the biggest happiest smile like the sun hit him) that I was genuinely caught off guard by it. Life circumstances made it that he disappeared out of my life recently, the context ended (unexpected, and I don't know if we will ever see each other again). I was really sad because I thought it was going somewhere. But instead of being sad about it I just want to be grateful for this cute, temporary connection. There was something very pure about it. Both shy, both not very confident people, both too careful but oh so into each other. Him maybe more so. It wasn't meant to be. I never thought myself a woman who could make grown a man nervous, stutter or just beam from happiness. But apparently I am and I will take it with me and be more confident next time something like this happens.