I visualize what I'm missing out on. Ie. If i miss a drama class I kick myself all day because each class is completely different and I KNOW I missed a surprise.
Knowing exactly whats going to happen causes me to not follow through.
also easy stuff that builds up momentum. ie. drinking water tieing up my shoes and putting on my jacket while i'm contemplating going for a run, then i'm already 1/2 way there by the time i have a chance to decide otherwise.