The encouraged behavior
Before we talk about the point of this post, let me introduce you to the story that triggered it:
There was a little incident at the laboratory where my girlfriend works, fortunately no one was harmed. While working with dangerous liquids, she spilled some of it on herself and on the floor. Being highly volatile, within seconds people were breathing the toxic fumes. However, to be really lethal, the liquid has to be drank or in direct contact with the skin. Since she spilled some of it on herself, the doctor told her that she should have gone in the laboratory shower designed for such cases.
That's probably what she should have done, but the idea didn't even cross her mind. Even after the incident, she's not sure she would have done it. Why? Because the shower is located in the middle of a hallway and has no curtains or door to hide the person (or at least parts of the person). If you want to use the shower, you'll have to stand naked in front of everyone for 30 minutes. The laboratory probably expects that people who get chemicals spilled on them won't mind being naked in front of others if it can save them from being burned chemically. What really happens is that people will hesitate and think that it's not necessary.
The shower is there to help people. People should use it at the slightest hint of danger, just like what happened with my girlfriend. Why then is it placed in such a way to discourage people from using it? They should make it as convenient as possible for people to get in there and use it. It should be placed at an appropriate location and equipped with a proper door so that people are not afraid to get in and to encourage people to use it.
The moment of hesitation
You should do the same with your applications and processes. You should make it as convenient as possible for people to use the features you want them to use. Encourage them to do the right thing. Whether you want people to register, to share links, photos, to use a time tracking system or anything else, make sure that there is no second thought, no hesitation and nothing to scare them from doing so. The moment of hesitation, the second thought is the moment a lot of people stop doing what you wanted them to do (see this study about the effect of CAPTCHA on conversion rates). If the shower had been in sight, with a door, maybe my girlfriend would have used it, in the hallway? Not a chance.
Make the encouraged behavior convenient.