Jamesy wrote:
I was cycling down the canal today and i encounterd an old couple. As i cycled past the couple the wife said in an agressive tone "manners". I then got agressive back and shouted at them arguing that i was not being rude. I came across these 2 people a few times on my bike and they were 'fairly' polite to me before. i have come into conflict with senior citizens before were i live since many can get agressive if do the smallest thing out of line.
Because of my AS i am very shy and lack eye contact. Do u think the elderly couple mistaked my lack of eye contact as rudeness? My dad has accused me of being rude before but often i don't realise when i am behving that way

I actually see a lot of things "wrong" in this story. The only fact is with your uncertaintly of why the elderly woman shouted "manners". There's a possibility that:
1) She was not talking to you
2) You "broke" a social rule that may have involved safety of others
3) The woman was startled
When facts are not present, always assume people have the best intentions at heart. Particularly with this elderly couple since they've been polite with you in the past. Also, when it comes to elderly people, there's always a possibility that their mental health is declining even without them being aware of it. And although some can be quite unpleasant, there are better ways of handling a situation than reacting aggressively, as you've stated here.
Next time, ask. Maybe you ARE doing something that's making people feel uneasy. If you don't know what that is, it'll likely happen again. It's always better to understand than assume anything and reacting by that assumption..