One of the most common barriers in decision making is not knowing how to make a decision in the first place.
It may seem strange, but many folks do not know how specifically they actually make decisions, or they use different decision making strategies in different circumstances without realizing it.
The solution, of course, is to take the time to learn a process that works.
Major barriers in decision making nowadays are fear and anxiety at getting it wrong. We have this idea that there is one best solution and that anything else is second-rate. This notion sometimes leads to an excessive gathering of information to the point where sometimes the decision never actually gets made.
One way around this is to make effective decisions as opposed to perfect ones. As General George S. Patton said, 'A good plan, violently executed now, is better than a perfect plan next week'.
In a similar vein, further barriers in decision making are the desires to avoid negative consequences and unpleasant aspects. This may lead to indecision, or simply the choosing of a safe option to avoid controversy. This can be especially tricky because often times there are unexpected consequences to any decision.
The reason things are unexpected is that they are unexpected! It's just not possible to predict these. Life happens and the world is chaotic. A useful skill is to be able to use whatever occurs so that you still get to achieve your outcome. That means you keep your goal in mind, but be flexible in how you achieve it.
Life numbing barriers in decision making is the idea of allowing someone else to make the decision for you. This occurs in a more subtle form when people wait for things to happen as opposed to making them happen. It allows people not to have to take responsibility for themselves and for what occurs.
What happens here, of course, is that you end up doing what other people want all the time. The answer here is not just to learn how to make decisions, but first of all you decide that you actually want to do what you want to do, at least some of the time!
The frames that people use for their decisions can act as barriers to decision making. 'Not thinking it through' indicates the time frame used was too short. 'What about the others?' suggests that the person is only thinking of themselves. An awareness of the frames being used and whether the decision holds true across many frames are useful considerations.
And, of course, the beliefs, assumptions, presuppositions and taboos of our culture may act as hidden barriers to decision making because we accept them unquestioningly.
Nothing like a bit of travel between many different cultures to point out to you what your own cultural beliefs are!