There are following below reasons, Why Shopping Cart Abandonment
[1]- High hidden costs at payment time which are not mentioned upfront(total of shipping and taxes cost and product price).
[2]- High shipping and taxes cost
[3]- A long and complicated checkout flow with multiple steps.
[4]- Fear of the product looking different from the picture/description.
[5]- Lack of payment options.
[6]- Website Browsing & slow speed Issue.
[7]- Forced customer account creation.
[8]- Terms & Condition & Return Policy not Satisfactory.
[9]- Credit Card or Payment declined.
[10]- Lack of Customer Support.
[11]- Lack of coupon code or discount code.
[12]- Need some research before payment done.