I wanna play ADC or Support BUT THE WAY IT WORKS....
If I queue up for a game and If I want any chance of being adc I cannot secondary support or I will GET support. So if I want to be ADC I have to secondary jungle top or mid for a chance at ADC. Usually 70-80% chance so far. But it still leaves me with the 20% chance I could of gotten my second role but I got top jungle or mid instead... 
I think other people know this so the trend continues if you want a role you never secondary support. So no1 is queued for support making it 100% likely you will get it if you make the mistake.
Mid, and steal all the kills :P