Shock Startup displays all the applications that are configured to be run each time you launch Windows. Some of them are really useful, such as any kind of drivers or an antivirus tool, but some other are not that necessary and can be safely switched off.
The good thing about Shock Startup is that it creates a different list for each user in your system, so that you can configure startup apps separately for each one of them.
Also, besides enabling you to delete elements from that list, you can also add programs to it, which comes in very handy to launch certain apps (for example, cleaning tools) every time Windows starts up.
On the downside, the program doesn't really give any information about each process except for its version and company. This means that you need to be sure about what you're doing before turning anything off.