1. More bars mean better cell service. Not true. Bars represent signal strength. You can have full bars but no service if too many people are making calls.
2. A camera is better if it has more megapixels. This is true to a certain extent. For the amateur photographer, the digital camera you already have is probably fine...even to blow something up.
3. Private browsing keeps you anonymous. People can still spy on your activity if you're using private browsing. It just means your visits won't be recorded on your own computer.
4. Macs don't get viruses. Macs are immune to viruses designed for Windows operating systems. But, lots of people are writing viruses for Mac OS X, so Mac users still need antivirus software.