I have spent much of my career working alongside salespeople, helping to sell software products to businesses. The best salespeople had a knack for candid and crisp communication, with prospects and colleagues.
One such salesperson took me aside one day after a sales meeting where I had demoed our product for a prospect.
"Can I give you some feedback?" he said (note: this is an excellent way to approach a critique).
"Can you stop saying 'I think' so much?"
"I say 'I think' a lot?"
"When a customer asks how to do something with our system, you say, 'I think you would do this, then this.' You know the answer, but you say 'I think' anyway. It confuses the prospect and makes them unsure. Does that make sense?"
I realized that I used 'I think' as a tic or to indicate that everything has some uncertainty with it. But prospects heard it as a lack of confidence - deadly in a complex sale.
Since that time, I have tried to be more direct and leave out tentative words like "I think" when I'm talking to customers or executives.
I'm also sensitive to others demonstrating this same tic. I heard a few "I thinks" this morning from a tech guy addressing customers, and that brought this story to mind.