Upcoming birth. They are going to have a baby.
Congratulations! When is the baby due? I'm so happy for you!
Birth. Someone tells you they had a baby.
Congratulations! Have you decided on a name yet? Have you picked out a name yet? What a cute baby!
Birthday
Happy birthday! I wish you many more. I hope you have a great day.
You haven't seen a kid for a long time and want to acknowledge how much he has grown.
Wow, look at you! You've grown so much! / You're getting so big!
Meeting a friend after a long time.
It's been ages! I've missed you! How have you been?
Graduation
Congratulations! Good job! All your hard work paid off! I'm proud of you. What's next? What are your plans for next year?
New job
Congratulations! I'm (so) excited for you! I wish you all the best. They are lucky to have you.
Engagement
Congratulations! Have you picked a day?
Wedding
Congratulations! I wish you a wonderful life together.
Anniversary
Happy anniversary! I wish you many more years together.
Sickness
Get well soon. I hope you feel better soon.
Surgery
(before) I hope all goes well. (after) How did it go? How are you feeling? I hope you have a speedy recovery.
Tough times
I'm here for you. If there's anything I can do to help, let me know.
Death
My condolences! I'm sorry for your loss. If there's anything I can do to help, let me know. How are you holding up?
You don't remember something
It's on the tip of my tongue. It'll come to me. It escapes me.
Prioritizing tasks
First things first. One step at a time.
Disagreeing
I beg to differ.
You want to leave a meeting
Pardon me, I need to step out for a moment. Excuse me for a moment, I'll be right back.