My daughter and I found that when we're participating on race day, the energy of the crowd helps us over some of the rough spots.
Also, my daughter makes each race a bit of theater. That is, she dresses up for the races, either with just some glitter, or feather headpiece, a tutu over her shorts or some other little touch of bling. For the Disney ½ marathon, she dressed like Minnie Mouse. Next year, she's going as Maleficent.
Some of our local races also have themes that make them more fun. On Thanksgiving morning there's the Gobble-Gobble Run, and the runners wear turkey costumes. There's another run (I forget the name) where the runners get pelted with bio-safe colored powder as they go by. My daughter loves all that stuff.
Yeah I want to participate the kind of races. THis time is the donation to the LOCAL SPCA. Nothing special but serious run. lol