Do I have to tip _well_, though? What's a neutral tip? I agree that while visiting your country, I should try and follow social norms there, but at least let's make official how much I should tip. I do not really have a very clear understanding of what good service is in comparison to bad service. Restaurant service to me is pretty much the same or, at least, I can't tell the difference.

A neutral tip for table service is somewhere between 15% and 25%. If you're in that range, you're not explicitly sending a signal to staff that you are exceptionally pleased or displeased. 15% might come off as a bit cheap, 25% as a bit generous, but the waitstaff will assume it's a you thing as opposed to a "your opinion of them" thing. Above or below that, and you're making a statement, intentionally or not. Less than 15%, you're saying you were displeased with the service you were provided. Only ever go below 10% if staff took deliberate action against you, and don't go back to that restaurant again.

At bars, 20%, or a buck or two a beer is perfectly acceptable. Cocktails should be tipped better, tied to how much effort it takes to prepare them. If you're going to be at the same bar for a few drinks, consider tipping generously on the first drink to help you get quicker service on future drinks.

At hotels, leave housekeeping $5-$10 a night, using the pen and pad of paper in the bedside drawer to leave a note indicating that the cash is for them.

10% on rideshares and taxis, $5-$10 on food delivery.

Pretty sure that's a pretty exhaustive list of places it's a significant faux pas to not tip. You'll be prompted to tip at a lot of fast-casual (order at the counter) places, but it's unlikely to be taken an insult if you don't. Anything higher than 10% is exceptional.