The best support from the sideline I've had was from a larger-than-life American in the velodrome at the London Games.
All she said from the fence was "C'mon Kiwi! You got this!" and I thought to myself: "Hell yeah, I got this. Cheers for the belief, lady."
It was in the semifinal and I had just rolled up to the start line. Tickets alongside the start line went for about $1000 a pop and you clearly had to be a huge fan to shell out for that. It was really nice to know people support you, no matter where you're from - they love sport and they support whoever is giving their best.
Looking back now, it doesn't matter what sport you're watching or who you're supporting, give whoever is out there playing the sport some support.