When you feel that a thing is happening because of other thing, you start doubting. That is the base of all misunderstandings (in case if the doubt is wrong) and detections (in case if your doubt is right). So some people cling in dilemma and waste their time. So to clear any doubt, the best method is correlation-regression kind of analysis. All doubts base on assumption of linking two things. So when you doubt, first identify the two interlinked things, present in your doubt. Then alter one thing and see. Alter the one which is completely in your hands. Then you will find out whether your doubt is correct or not!!! Example, when you think that your friend is spending time with you to get a benefit from you (like money, room, vehicle, food, ect,..) stop supplying that benefit for few days and see rather than ruining your relation by swinging in dilemma….