For work flying:
White shirt, uniform trousers.
Bars when absolutely required, but they're taken off at the earliest opportunity and hidden in my flight bag / pocket. In some parts of the world they make the difference between a standard challenging airport experience and being stuck overnight while bribes filter through official channels.
In some circumstances I'm expected to wear a grow bag. With bars. Again, bars taken off asap and a hi-vis is a useful aid to hiding them.
The reason many professional pilots take off their bars is because it's considered to be pretentious and ego-driven to wear them outside of the office. It's broadcasting to the world that you're a pilot. This broadcast also implies you're insecure in yourself since you need to tell the world what you are. Rather like "loadsa money" needing to flash his cash, or a president needing to tell everyone how great he is. A good pilot doesn't need to advertise anything.
A grow bag is slightly different. It's a piece of safety equipment, and there are certain types of flight that might be considered somewhat more risky and therefore additional PPE could be relevant. And if you determine that your flight in a C152 to collect a bacon sarnie is risky enough to warrant a grow bag, fair play to you. I'm not going to judge that. I will judge on the basis of how many badges / gold braid / bars you choose to adorn yourself with, since this has no impact on safety and mostly makes you look like an arrogant idiot (see above re great presidents).
For fun flying:
Aerobatics, open cockpit, vintage or test flying: grow bag. No badges. Occasionally a simple name badge where appropriate. For these flights I'll often wear gloves.
Any other flights I'll wear jeans or cargos, t-shirt, trainers and avoid the use of a hi-vis unless absolutely necessary.