While it might be tempting to take that bar of soap and shampoo from your hotel room, you’re best off leaving it if you don’t use it.
Sure, you already paid for the hotel and consider it a part of the service, but you probably already have a perfectly good bottle of shampoo and plenty of soap at home.
The materials (both plastic and paper) cost money to produce, create more waste, and often get thrown away when people get home.
So if you aren’t using your toiletries, leave them for another guest who actually needs it to help keep the waste down.
Doing this also saves money long term for the hotel, helping keeping its costs down, eventually passing those savings on to you.
If you do end up taking them and find them sitting around, consider donating them to a local shelter instead of throwing them away.