Anything worth doing tends to be hard and challenging.  

It’s my opinion that military service is worth doing.  It’s a respectable career field, and I’ve enjoyed it but it’s also been hard and challenging.  And as I was thinking about what I was going to say…

Don’t count the days, make the days count. 

There are no secrets to success. It is the result of preparation, hard work, and learning from failure.” 

— Colin Powell