I think the reason that INFPs and INFJs put things off are very different, even though to some the result could look the same. For me too, it has to do with a nebulous kind of fear of not doing as well as I envision the result should be or disappointing someone else. I can even understand in my head that putting something off or avoiding it has worse (and potentially more disappointing to others) consequences in my life than not making a perfect job of it, but it still is difficult when I'm really emotionally invested to get over it and get on with the job.
Sometimes Ni just brings things into better focus at the end so I can easily complete the task (it's answered the questions that were paralyzing my progress), sometimes it's a matter of seeing the problem in better perspective so I am not so emotionally involved and can see what I need to do, sometimes I find having a very different type of person than myself helping me can be useful (as long as they stick with me for the whole process - otherwise I run into more unaswered paralyzing quandries down the road). I'm much better as I've grown older. Breaking the task down into manageable chunks can help still some of the rising panic and getting on with it rather than waiting for something to change. As I've gotten older I also find that I can see other people's negative opinions of me as not being the very end of the world, even if I still find that uncomfortable.
For what it's worth, I'm an enneagram 1w2 or 2w1 as well.