Decisions also can have either a large or small impact on your life, depending on what it is.
Small decisions, over time, can have a negative impact (i.e. eating that one chocolate chip cookie every night before you go to bed may lead to obesity).
The same can be said about positive decisions too, like reading one nonfiction book a month. Over time, you will not only increase your knowledge, it'll make you more valuable and eventually more successful.
Now I don't mean this to say that you need to look at yourself in the mirror every day like Stuart Smalley (Al Franken's character on Saturday Night Live) and tell yourself that you're wonderful either.
Recently, I made a decision to resign from my part-time job. It was a huge decision--one that took several months to actually make--for not only had I been employed there for 12 and a half years, I enjoyed the work. However, with caring for my wife, kids getting older, and my writing taking up more of my life (and with writing being something I truly love to do), I had to turn down so many shifts that I was offered to work that it didn't make sense for me to stay on any longer. It's sad to leave, for I made many friends there, but I'll still see them around. It's not like I'm leaving this mortal land.
The biggest decision that my wife and I made last year, regarding her leukemia treatments, was whether to go with a bone marrow transplant or not. The doctor gave us all of the options, but for that one, the decision was easy: we go with the bone marrow transplant, despite the immediate risks, for the long-term risks are less.