is the way I dress suitable?

I am male. In my free time I like to dress in T-shirt, short shorts, long black kneesox and converse trainers. My friends say I look good but when I'm out and about I do hear people laughing and I think maybe they're laughing at me. Do you think a man who chooses to dress in this manner looks...............

Do you have any advice on how I should change my look, if you think it's necessary?