What could have been the reason why he lost interest?

Ok, so, because he didn't tell me and now it's to late for me to ask directly, but I'm obsessing over it, I ask you for an opinion.

I meet this guy in a group of friends, there was some flirting, looking and little talking and I have the doubt he was attracted to me, one day he asked me out. I get very nervous because I hate dating but I pretty liked him so I said yes. We finally met outside and have a common first date but something went off after that. He was very shy and nervous at first and I honestly were a little uncomfortable with him because I couldn't understand if he was angry or repent for asking me out. I've come late, my fault, problem at home. Anyways, I were used to him being a little weird and not so clear to understand, he could seem a little harsh sometimes but if encouraged with kind and friendly interactions very open and nice, the point is we knew eachother yet so were not a blind date. I dressed very simple, like everyday because he had the habit to staring (litterally) my boobs while talking and I didn't like that so much so I decided to not show him that much. However he also dressed poorly (not because I wanted him dressing nice, I already liked him I could't care less , but I just thought that he wasn't interested in seem cute for me). We talked about a lot of arguments but nothing deep, same things as usual, anyway at one point I went a little off because he was really stiff and seemed worried to not make it look too romantic. He offered to pay because he asked me out so I accepted first but at the end I ask to pay togheter because I wanted to order another thing and while he doesn't, so I didn't wanna make him spend too much, he suddenly get up fast while I was still consuming because I was doing late for my train (i told him i had to take that train but there was another after no reason to rush). Basically, he could't wait for it to be over. I went super off then and rush too to get my train too, while I was get on he stopped me to ask "I want to ask you if you could be interested in seeing each other another time and if you could text me when home". I was tempted to say no because how the date went but damn I liked that guy so I said "yes sure". I text him at home and he text me back something like he liked my company and talk and thanks to me and bullshit like that. I responded that I would have liked to talk about something with him in person but definetly I have fun too. I swear my interest was clear, his not so much so I wanna talk about it with him because I hate when someone says nice things just to not hurt me, I prefer clarity. He didn't respond. I meet him again in ordinary life and he was weird and uncomfortable, I was friendly for a while but we never have the occasion to talk seriously. He text me something stupid and random at one point that could have never bring up a conversation, I respond however and he didn't text back. After that I decided I was over it and completly distance myself from him, stopped being open just "hi". He never reached out again.

Now, I could have probably asked him directly I know but I didn't feel to do it because the circumstances and because I was feeling hurt and rejected. I never go to date because I hate them and rarely like someone. I genuinely liked that guy so I was disappointed and feeled stupid because I thought he liked me too at first. But the lack of clarity pissed me off, I mean, he knew my aspect and my person yet, nothing so serious or so different happened during the date if not more embarassement. What the hell happened? Why a person should change his mind so rapidly? What could have been? For me the possibily is he wasn't into it from the start and probably have other interests that's why he was weird but still happy when I gave him attention and he could just stare at my boobs, but if so why the hell asking me out at first place , if it is just a stupid thing like that simply why delude people? Or maybe he notices something about me he disliked, but I can't figure out what could have been (a lot of things actually but nothing that he didn't know before or that are so serious to not put a little effort not even for something slight and fun). Have you ever had experiences like that? What's your opinion about it?

P.S. a stupid though, don't hate me, I'm already hurt but I was comparirg this to my first date with my ex when we've been out togheter all the night and kissed at the end, I was dressed poorly also then and my ex too seemed a little weird and rigid, completly became courageous insyead and kissed me when during the evening I changed my clothes because I was hot. I think I'm becoming paranoid but is the amount of boobs that you can immediatly, not in general, see that motivate someone stopping being "shy" (translated disinterested). I hope is just a paranoia and I'm overthinking this too much.