I struggle to make decisions period but for different reasons depending on the type of decision that it is. For example, I do (contrary to popular belief) take my commitments really seriously, once in I am in for the long haul and so I agonise over big decisions. I also factor in the feelings of others perhaps a little too much and so it makes the process quite difficult for me. Then smaller decisions I just don't make for a simple reason and that is I just don't care enough about things to do so. It really drives my friends up the wall but I have just reason for taking this tact. I'll give you an example of a typical conversation between me and my ISFJ friend;

Friend: So where shall we go for lunch and at what time?
Me: I really don't mind it's up to you
Friend: Just make up your mind, you never make a decision.
Me: But that's because I really dont' mind
Friend: Just make a decision for once in your life
Me: Ok well what about X place at X time
Friend: Oh that place is crap, i hated it there last time and I have a hair appointment at that time
Me: Well you decide then
Friend: How about place x at x time
Friend:*rolls eyes* see I ALWAYS end up making the decisions!