When working for a company you need to think carefully about loyalty. This goes both ways in a job – you hope that you have some loyalty of your boss and the company you work for but you also need to show them the same. Many employers expect their employer to be understanding should they have to have time off work due to family issues or illness or to be flexible in their working hours to fit in around school pick ups etc. but they also need to ensure that they also are willing to offer their employer the same courtesy.
It may be that occasionally you are asked to work a little bit later once in a while or that they may ask if you could take your lunch break a bit later to help out with something urgent that has come up. Putting yourself out on occasion will show them that you are also willing to be flexible.
It may be that there comes a time when you are head hunted by another company. They may seem like they are offering you the world but it is important to think very carefully before jumping ship as often it is not only the money that you have to consider.