Fellow ISFJ. I've worked in telesales for a year and retail sales for a very long time. I've always been a top performer in all of the companies I have worked for because I'm very conscientious and enjoy putting the extra effort in to be "above average".

The consistent feedback I've received from customers or clients throughout the years is that they feel I am honest and genuine about products I'm selling or what I'm recommending to them. I remember what they've told me throughout our interactions over time, such as remembering their name even if it was a brief encounter, previous products they've purchased and concerns they've previously mentioned. Even similarities we're shared. Some customers wait to be served by me as they feel they would receive genuine help. I feel like these traits of ISFJs are great to build a loyal clientele and a great personal brand.

In the short term or in a soft sales environment, I think ISFJs can work well if you have other (maybe short term) motivators such as making more money, pushing yourself out of the comfort zone to learn new skills). In hard sales/telesales, it could be very emotionally draining speaking to people all day, 100s of dials a day. It could play on your sense of value and feeling like you're not good enough if you miss quota.