Meaning of 苦 in Japanese

なんの苦もなくその場所を見つけた。
He had no difficulty in finding the place.

ご苦労様でした。
Thank you for your trouble.

アリさん、今日もご苦労さんだよ。はい、角砂糖あげるよ。
Hi Mr Ant, keeping up the good work today as well. Here's a sugar cube.

気苦労で彼は急にふけた。
Care aged him quickly.

ご家族の皆さんによろしく。
Give my love to your family.

こんな狭苦しい部屋からは一刻も脱出したいよ。
I want to move out of this cramped room as soon as I can.

私は苦いものが好きだ。
I have a fancy for bitter things.

彼の家族はかなり生活が苦しい。
His family is rather badly off.