Buying time, expecting attention
In the early 90's I once worked on a project to establish a sales/marketing culture for a mid-tier pharma company establishing it's own Australian operation for the first time. Their products were important, if a little mundane and somewhat limited in scope. The company had identified that as the size of the business meant that there was almost no scope for career advancement it was going to struggle to recruit effective salespeople.
Their solution was to staff the sales force with experienced women looking to reenter the industry after having children. Prima facie it was a good fit. The company needed solid experienced performers but who weren't interested in promotion and the women wanted to rejoin the workforce but on more sympathetic, less careerist terms. With the right HR attitude to flexible working hours it looked like a 'win-win'.
For a while it worked well enough. The new team was highly energised and quickly established a healthy, credible presence in the marketplace. Sure, the job-sharing and ongoing maternity leave coverage issues required additional Head Office and sales manager admin but no more than had been anticipated.
About nine months later, after the initial euphoria of launch had died down, the mood changed abruptly. Both management and the individual salespeople were suddenly, totally disenchanted. The company expected the women to still be grateful for the opportunity to rejoin the workforce on such sympathetic terms and that gratitude to manifest itself as greater attention to detail. The women couldn't see what the problem was: they were turning up and doing the job (sick kids who needed early collection from child care notwithstanding) weren't they?
The women were selling time only whereas the company thought that their (complete) attention came as part of the package. Within a year the complexion of the team had shifted back to the usual blend of unambitious old stagers, thrusting careerists and a few women with young children but decent family support to allay the early-pick-up-from-child-care-issue.
No pregnant person can give an employer his or her complete attention. Ditto for anyone with a new baby. It doesn't matter of that baby is real or metaphoric (i.e. a nascent IOS app, a comedy career or a that business you're starting up on the side) and it's no less true if both you and your employer buy into the fiction that selling only your time will be sufficient.
Something you love more than your job is always going to take attention away from that job. Because in part that's what love is.