There's a fine line between being stingy and being frugal. You can choose to not waste money - that's frugal - or you can choose to hoard your cash - that's stingy. It's such a fine line because what counts as a 'waste' and 'basic necessity' is often subjective and very open to debate.
Here are a few things for consideration when talking about being frugal versus being stingy.
Choosing a living space. It can be argued that for your place of inhabitance, all you need is space to sleep, eat, and shower, and that's that. I think that may be true for some people, but for many people having the basic minumums could be a hinderance on productivity and happiness. I think that for what I know about myself, I can be perfectly content with just enough room for an air mattress, and some space to set up my laptop and a couple of plates for food and food I consumed the days before (since I refuse to clean up often). The thing is not everyone can live like this. Some people genuinely will become unproductive or demoralized without a certain level of comfort met. You have to decide if you still want to work with those people - if you do, you have to learn that this means you can't try to force them to be too 'stingy' - or if you want to find people like you. So being "frugal" or "stingy" in this case is just what the level of comfort someone must have before their mood or work is impacted. Again for me personally, my frugal tends to be a lot of other people's stingy. I'm okay with very very basic needs.
What to eat. Again, this is not cut and dry. You can decide to feed yourself the basic nutritional needs and could consider that frugal. But almost everyone else would find that stingy. I actually have found that empiracally, I do get a happiness boost if I eat good food over just basic cheap food. Being full is important, first of all, but being satisified can be just as important. It's all about morale, I suppose. Being frugal here is just trying to buy groceries on sale as often as possible and planning ahead, while stingy would be just always buying the dirst-cheapest thing available.
What office supplies to get. There are some clearer measurable metrics here, so this is probably the most objective out of the three. I think you could clearly measure productivity boosts that an extra monitor provides, or a separate keyboard/mouse, or even quality pens/pencils. I would say with office supplies, it can be good to spend some money here. Obviously, don't go buying huge monitors for everyone and their mothers, but make sure you don't limit your productivity by not having something you need. Being frugal here, I would say is just trying to get the best deals for the things you need. Being stingy would be telling everyone that just a laptop is enough and to go with Toshiba or something ridiculous like that.
Overall I think being frugal means, spend the least amount of money possible so that you can be productive without thinking about what else you might need or having things get in the way. Being stingy would cause you to really be worn down by the environment. That would be bad.