1. You don’t need to change your oil every 3,000 miles or 6 months. This interval is typically much longer for modern engines and modern oils, and with a good synthetic oil it may be as long as 2 years and 15,000 miles. Based on a good comment below, I will warn that oil life can vary drastically, and waiting too long can seriously damage your engine. For almost all drivers, anything under 5,000 miles is excessive.
2. You don’t need to change your fuel filter regularly. Nowadays gas is very, very well filtered from the pump, and you barely even need a fuel filter on your car at all. Unless your car was particularly abused and your gas tank rusted or fuel degraded in the tank, the filter should be very clean.
3. Changing your transmission fluid won’t damage your transmission. If you’ve left fluid in your transmission for too long, then you can get buildup that comes loose as the fluid drains and causes your transmission to not work well, but this would happen eventually even if you didn’t change the fluid.
4. In modern cars, you do not need to release the parking brake if you are letting the car set for a long time. Parking brake systems no longer stick as badly as they used to, and are safe to leave engaged for long periods of time.
5. Pod filters are not an improvement and do not make maintenance easier. They look cool but most of them don’t do anything and are actually worse than a stock air filter.
6. Blinker fluid doesn’t exist and you don’t need to refill it or get it changed. Someone is making fun of you.

Edit - here’s a big one that I missed:

1. Doing something yourself will not “void your warranty”. Under the Magnuson-Moss Warranty Act, it is strictly illegal for a company to void your warranty for using non-OEM parts or labor to fix your car, unless they can prove that doing so is negligent. Automakers have paid large settlements for lying to consumers about this.