Mind-blowing

If something is 'mind-blowing', it greatly impresses, excites, or surprises you. You can also say that something 'blows your mind'.

Examples

• The support I've received from colleagues since I was unfairly dismissed from my job has been mind-blowing! I had no idea they thought so highly of me.
• You must see that movie. The ending will blow your mind!
• Seeing that pianist perform live just blew my mind. I have never witnessed anything like it!

Lose (your) mind

A person can be said to have 'lost their mind', if they become mentally unstable, extremely frustrated, or do something foolish. Mostly used figuratively. 

Examples

• If I hear that stupid song on the radio one more time I will lose my mind!
• I can't take the stress at work anymore. I feel like I'm losing my mind!
• How can you say something like that to your boss? Have you lost your mind?

(Be) mindful of (something)

If you are 'mindful of something', you are conscious or aware of it.

Examples

• I'm mindful of the fact that Adam has problems at home, so I don't want to burden him with too much work at the moment.
• The manager told staff that, going forward, they needed to be mindful of the new policy with regards to the handling of complaints.
• Lawyer: "My client was mindful of the treacherous weather conditions, which is why he wasn't speeding at the time of the accident."

(I) hope you don't mind

'I hope you don't mind' is used in order to be more polite when saying something that might annoy, upset or embarrass somebody.

Examples

• I hope you don't mind, but I rearranged some things in your office while you were away.
• You really look as though you could do with some time off work. I hope you don't mind me saying that.
• Hope you don't mind me asking, but did you sort out that problem you had with Chris? 

Cloud (your) mind

If something 'clouds your mind', it makes it difficult for you to think or understand clearly.

Examples

• I know you're disappointed, but don't let negative thoughts cloud your mind. I'm sure you will bounce back from this.
• My concern about Emily is clouding my mind. I can't seem to focus on anything else.
• Gary wasn't thinking straight that night. Alcohol had clouded his mind.