Hearing Ukrainian for the first time, if you're Russian, sounds like you're hearing a Russian dialect you never heard before but understand 90% of, bar some words you've never heard. The languages are that close.
Polish, otoh, would baffle a Russian at first, you'd grasp quite a bit but you know you're hearing a foreign language, Slavic but foreign.
Hearing Ukrainian for the first time, if you're Russian, sounds like you're hearing a Russian dialect you never heard before but understand 90% of, bar some words you've never heard. The languages are that close.
Polish, otoh, would baffle a Russian at first, you'd grasp quite a bit but you know you're hearing a foreign language, Slavic but foreign.