Having kids does ruin your life. But it also makes you realize that that life was worth ruining. I miss having loads of idle time, hanging out with friends every weekend, etc. I also miss the basically complete financial security I had before having to support a family as a sole earner, and eventually I realized I needed medication to cope with the anxiety it was causing.
But my son is awesome, and there's absolutely no way I'd trade him back for any of that.