Maybe that's more realistic than "be a better working mom". One thing I've discovered talking with my fellow moms — working and nonworking alike — is that we're all plagued by a similar sense of inadequacy. I feel guilty I'm not around more for my kids;  a friend who works part-time worries that she's not providing a strong working woman role model for her boys. 

My husband observed that the best indicator of the unrealistic expectations on us moms is the number of different phrases about "bad" moms: smothering vs neglectful. hovering vs cold, etc. Whereas the only derogatory thing you ever hear associated with fatherhood is "absent father". In other words, dads get full marks simply for showing up; moms have to worry about being too loving or not loving enough, too engaged or too distracted.

All those labels go through my head when I've spent a long day at work or (more frequently) had a hard time disengaging from work and really engaging with my kids once we all get home. I try to remind myself that (a) everyone blames their parents for something (!!) and (b) whatever my regrets at not having more time with my kids, I'm not cut out to be a full-time mom. I'm a much happier, relaxed and engaged mom for having work that I love, and nothing is better for my kids than a happy mom.