I went in 04, 05, 06, 08 and 09. I camped the first two years. I didn't go in 07 becuase I was jobless and in '10 we had a desitnation wedding in May so that blew the budget. Kids arrived in 11 and 13. So, basically, life happened. I had many friends go last year, and wished I could have gone.
I actually like festivals in general. I like music all day long. I like the scenery. I like the nice weather. I like totally disappearing from my normal life for a weekend. I understand it might not feel that way from someone from LA or in California, generally.
In 05 I did Coachella, Lolal and ACL and all three weekends were 100+ heat, so those really cummulatively exhausted me.
The biggest problem for Coachella for me (other than the flak I receive for leaving the wife with 2 little kids for 4+ days) is that I am too old to camp in that heat, which means I have to stay at a hotel or condo or house and use the shuttle. Which means I have to leave like 90 minutes before the first act I want to see. Which means I have to get up at a decent hour and can't relax. I am too old and lazy for it.