Do other sellers have problems with buyers not leaving feedback

[nhfd4976]

Do other sellers have problems with buyers not leaving feedback.  I even once I know their item has been delivered leave them a email making sure they received the item, They like it or have a problem.  If they like it to leave me positive feedback if there was an issue we agree on how to settle it.  But I would say 10% of my buyers do not leave feedback.  What do you guys see as a trend.

Thanks

Jeff