Is being selfish the secret to happiness?

It's 6.30am and I'm kissing my half-asleep son goodbye before I leave to catch the train.
"Ditcher!" he mutters, sleepily.
This is a word used frequently in our household by my 10 year old.  It has become his stock response to any situation where someone other than me will be looking after him outside school hours i.e. he's being "ditched", hence I am a "Ditcher".
The word is usually accompanied by a cheeky grin and I am comforted by the humour in those exchanges but, that day, I left home with a feeling of discomfort that lingered for a couple of days.
The discomfort was, I realised, because I was putting myself first. 
My (tangled) thought process went something like this:

• That piece of work sounds amazing! I want to do it!
• Q: But what about the impact on others? 
• I want to do it! I can do things to reduce the impact on others! 
• Q: But what about the impact on others?
• They'll be alright!  I want to do it.  I'll do it anyway!
• Q:  But what about the impact on others?
• I am a selfish, horrible person and a bad mother.....

And even though I've been here before and I know this is not the truth, it still felt rubbish.
This situation isn't specific to working parents either.  A passing comment from a friend, an instinctive reaction from your spouse, even sarcasm from an unpleasant colleague can have us questioning ourselves.
There's nothing wrong with a bit of reflection.  But what happens when we give others opinions, feelings or requests far more weight than our own?  And what about when we discount an option without even discussing it because we are concerned about someone else's reaction? 
I'm not suggesting you ignore the impacts on or opinions of those around you. Asking, listening, talking and exploring options with people who matter to you can be a powerful part of the decision making process.  The secret is using that information (rather than guesswork or presumption) alongside your own area of expertise - you.
You know what brings out your best.  You know what fulfills you, what drives you and what gives you goosebumps.  You know what is most important to you and what you want and need around you to be successful (whatever your definition of success).
When we are doing things we enjoy, with people we enjoy, we feel good.  When we feel good, we are nicer to be around.  When we are nicer to be around, our relationships with others improve.  There's a positive ripple effect which benefits us and those around us.  
I know I am a better person when I am fulfilled.  I am a better coach, a better friend and a better mother.  It can feel like a delicate balance at times and one I will certainly get wrong on occasion.  But only I can decide where the balance lies.
So whether it's investing in that course, going to the gym before you go home, exploring a new career path or choosing exciting work rather than the school run, if it makes a positive difference to you, it will also make a positive difference to those you care about.
I'm going to be a "Ditcher" again shortly and I'm fine with that.