Why were the girls in the shopping mall laughing at me exactly for?

Yes in the mall when i was walking with the shopping cart i saw 2 girls in their 20s standing ane it was blocking my way... i was kinda shy to ask excuse me... so i was waiting for them to move and when they saw me standing there they were laughing at me and then let me go and were still laughing at me... were they laughing because i was shy?