When the native speakers say," I like your shirt." or "I like your shoes."
Something that you're wearing at that moment.
What is the true meaning? Do they mean your shirt is a nice one? or do they really like your shirt?
Well, if the person is being sincere, the meaning is that they like the style and/or color of your shirt/shoes. It pleases them. Maybe they would like to know where you bought it so they too can have one just like it. Or maybe they like that particular style or color on you. It makes you look good and so they want to tell you to make you feel good. In general, admiring someone's clothes is a way of making friends, of making people feel comfortable, feel good about themselves.
If the person is being cheeky, as FRC notes, it means they don't like the style and/or color of your shirt/shoes.
Pat: Wow! Nice shirt, Max.
Max: Haha! Funny. This is my old painting shirt! I wear it only when I am painting.
Pat: Yeah, it's ugly.
Pat Wow! Nice shirt, Max.
Max: Thanks. Do you really like it? I bought it at the new mall last week.
Pat: Cool. I wonder if the have one in my size.