You try a new beer that comes from a brewery that was recently built near your house. It's surprisingly good. You're telling the people that you're eating dinner with that you like it.
That's not half bad!
idiom, praise, understatement 
Your name is complicated to pronounce for English speakers. You're introducing yourself to someone that you just met, and explaining how to pronounce your name. You say:
I know; it doesn't exactly roll off the tongue.
apology, idioms, pronunciation, understatement, 日本語サポート 
Your friend was using your camera and accidentally deleted all of the photos that were saved on it. You don't want to seem too angry, so you say:
It's not the end of the world.
disappointment, mistake, set phrase, understatement 
You have had a bad experience when you called your cable TV provider to get help with a problem. You're on an Internet forum where people are discussing their experiences with cable companies. You write:
Time Warner Cable's customer service leaves much to be desired.
companies, customer, formal, service, set phrase, understatement You're a single guy. You met a girl at your friend's party and hit it off with her. Now your friend is asking what you think of her. You say:
She's pretty awesome.
adjective, adverb, casual, compliments, dating, party, understatement, 日本語サポート You are out shopping with your girlfriend. She asks you what you think of a pair of shoes that she likes. You don't like them very much. You say:
I'm not crazy about them.
casual, clothing, idioms, shopping, understatement 