To prove it is not just a carelessness thing - when you're walking on the street and really really happy, and everyone can see - sooner or later you will come across a miserable asshole, who, given he/she has the ability to, will do something to get on your nerves - be it walking into your path, providing poor service - just anything they can in an attempt to ruin your positive mood?
Why? Just because they can't stand you being happy.
Beside acting miserable, which is not really viable option as it defeats the purpose, the only solution is to smile and be MORE happy to the person who is 'challenging' your happiness. I believe the mistake is made here for most people as they do not recognize the dynamics of sadism and the apparent act - but I believe once you return more happiness to the offender they should get the message and leave you alone, even though you may have to swallow a ticket, but in this day and age the legal ways someone can do something just to fuck with you are very very limited.
Better still, develope a radar for miserable people who are likely to offend against you and LAUGH at them before they have even made their attempt.
