Allotments 4 All

 i work in a meat processing plant  in the canteen one of the jobs is picking up dirty crockery which is beside a glass partition couple of lads was playing a joke on me last night  by banging loud on the glass then looking away and giggling this happened a few times  the next time i gave them them the flick off sign by rubbing my face with one finger you should have see the shock on  the youngest ones face that a old lady my age would use such sign language could nt help laughing   at his expression

They were probably expecting you to get indignant.  What you did was very funny, because it was unexpected.   ;D