Servo Speed Changer with Buttons
There may be better ways to mitigate button bounce. Check this link for a discussion on button bounce and example code to work around this problem. In your code, it appears you can not press your buttons faster than once a second.

Determine if the servos you are using are capable of the range you are demanding.  Some servos only travel from 0 degrees to 180 degrees.  Your code is asking the servo to travel from 0 degrees to 360 degrees.  Also, it is unlikely that any normal servo can travel this far.  Most servos use a potentiometer as a feed back sensor.  And most potentiometers can only be turned to something less than 1 full revolution.  

It is likely you have not given the servos enough time to move to the zero degree position at the start of each of your 3 loops.  Understand that normal servos can not make complete revolutions.  They need to stay within their designed limit of rotation.  If you want to start over at 0 degrees you need to allow the servos time to rotate back in reverse to the 0 degree position.

Consider your last loop.  You are asking the servo to move from 0 degrees to 360 degrees in 10 degree steps.  You are allowing 20ms per step.  That means the servo will be demanded to move almost a complete revolution in (((360 / 10) * 0.020 = 0.72 seconds) less than a second.  Some but not all servos can move that fast.