i recently got burned because at some point in the last few years Excel decided it would be better if it attempted to use localized thousands and decimal separators.

    item,cost,currency
    "Socks",1.234,USD

Represents socks costing about a dollar in countries that use '.' as a decimal (most) and about a thousand dollars in countries that use a ','. In locales using a decimal period '.' double clicking will open the CSV just fine. In locales using a ',' it comes in as text but the default settings for text to columns use localized number parsing but still let you choose a now ambiguous comma as a column separator. I'm 99% sure it didn't used to do this as we've been making CSVs for the same clients in the same regions (Netherlands) for years and only more recently have they had this trouble.

Edit: I've used Excel for at least 20yrs. I thought i new how to use it and how to search it's docs. This is the only article I've found online that mentions how to handle this as a end user. Near the bottom under "Converting International Number Formats" where it of course assumes you have decimal comma and need a decimal period.

https://www.howtogeek.com/407217/how-to-use-text-to-columns-...

I did also find a 20 minute youtube eventually