When working as a sales rep many years ago I remember playing back one of my calls - an invaluable exercise for anyone in sales.
Once you get over the cringe factor of listening to your own voice you start to really learn some things about yourself. And I don't mind admitting I had some major flaws.
I realised I had certain 'filler' words which most people do. My main one was 'obviously'. I must've been saying it about 20 times a minute - urghh!
Another thing I would do would be to ask a question and then go on to answer it myself (with the response I wanted to hear!) How irritating! I just wouldn't pause and let the client speak.
Apparently I knew everything about their business and challenges without their input. This approach will guarantee mediocre sales results at best, based on assumption and generalising what you think you know about someone.
This one exercise taught me so much about myself and quite literally made me a better salesperson overnight.
I was infinitely more self aware of my weaknesses.