The reasons for various erection problems are becoming more and more common in lifestyles that we lead which cause them. They are usually caused by a few reasons and tackling them is not Everest-like climb that many would like you to believe. They have driven men to depths of depression, even to point of suicide, because they do not want to discuss their problem with anybody.
They do not want to discuss erection problem with their partner let alone a trained professional who deals with such things day in and day out. Erectile problems have also been reason behind breakdown of many marriages because of lack of communication between two people involved.
Probably biggest cause of sexual performance problems is stress. Not being able to leave woes of day at work will almost certainly lead to an erection problem of some kind, so it is important to make sure there is a break in day between end of work and before any other type of responsibility that needs to be taken care of: Sex in particular!
Another very common reason performance anxiety. It is a common reason for sexual performance problems because once it starts it often has a snowball effect which makes it progressively worse until it is almost impossible to have sex.
Put simply it is impossible to have an erection when all you can think about is having an erection. The more you try to "will" an erection into being, less you are thinking about erotic thoughts that you actually need to be thinking to have an erection in first place.