Should I quit my job? (Opinion)?

Around 2 weeks ago I decided to quit my job (Could have been a little spur of the moment). I called my work and spoke to the istant manager (The manager wasn't in the store at the time) and he asked to to bring in a letter of resignation. About 3 days later I went to hand in my letter. My manager was in store, and asked to speak to me. He asked me why I wanted to quit. (Sorry for not mentioning this earlier, but I'm, a casual sales istant.) I told him that I felt uncomfortable 'pushing the sale' (Telling my customer to buy something because it's more expensive or to add items to the purchase.) because I thought it unethical. I'm a Christian and I sometimes feel that the attributes that my faith holds as important are comprimised. Also, the other staff are all older than me (3 years minimum, but most are around 10 years older than me) and I feel as though I have nothing in common with them. This is more of a minor gripe, but I have had a couple of abusive customers.