Something I learned the hard way in Saudi-Arabia was the importance of saying mashallah. When I had just started working as a nurse I was full of excitement and I was very talkative with my patients. I wouldn't give second thought to complimenting on a Saudi woman's beauty, admiring her pretty dress or beautiful children. Then one day when I was returning to work and was anticipating on having the same patients assigned to me I was in for a surprise. The family had thought I had been "too friendly" and had complained to the head nurse about me. They had mentioned how I didn't say mashallah when I praised their kids, despite them requesting it. They had instructed me in Arabic to "say mashallah" and I hadn't understood so they had gotten suspicious and requested another nurse. I was devastated, but I took it as a lesson.
So what does mash'Allah mean? The literal English translation is "as God has willed it". It's used for whenever someone or something is being praised or admired. It's supposed to be a reminder that all good things come from God and are blessings from Him. Saudis and other Arabs also strongly believe that saying it prevents the "evil eye". Sometimes Saudis might say mashallah when just looking at something nice.
When lots of children are present and people are talking about them, every other word seems to be mashallah! It can be quite frustrating to always remember to say it, but for Saudis it comes naturally and they expect westerners to know to say it too. The family at the hospital obviously was afraid that I had given them the evil eye. It might sound superstitious to some, but it's dead serious business here.
So be warned, if you're coming to Saudi-Arabia and see a cute baby (they are everywhere) don't forget to say mashallah!