Selling will drain your ego if you let it, and you will recharge your ego by draining the ego of your next prospect. When you get in front of a real prospect, you will show off your product knowledge... using all the insider "buzzwords" to make your prospect feel "not ok" thus making you feel "Ok" - only to lose the sale.
Product knowledge is critical as long as you don't tell anyone. Using technical knowledge or insider terminology will intimidate your prospect. Most people will not sacrifice their ego to ask you the meaning of technical terms. They will shake their head "yes" only to say "I need to think it over" because you used your product knowledge to try to impress rather than using effective questions to develop the personal and emotional reasons they may have to do business with you.
Which example works? "Mr. Jones, our product meets all ISO 9001 sub S standards with widget-metric guarantees" -or- "Thanks for telling me about your plant - what standards are you working under? Last week, we took on a new client that needed the ISO 9001 compliance." Telling a story conveys your product knowledge without showing off and trying to impress.
So check your ego, don't show off, ask questions, and tell stories to succeed!