5 minutes is pretty weak. Most people say to try anime for at least 3 episodes because of how the plot changes
Anime
Anime is hand-drawn and computer animation originating from Japan.
Anime; the one thing that gets us closer to each other and brings us together.
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Why? If he does not like it respect his tastes maybe?
Ask him first why he didn’t like it. You can’t convince him otherwise if you don’t know why it doesn’t interest him.
The more you want him to watch the worse his exp might be just suggest to him one and it'll be fine.
Tell him he is missing out on incredible feats of heroism, memorable kickass action, incredible animation and political drama by not watching tengen toppa gurren lagann
I don't think you can say anything to him that will convince him. The more you will try to convince him the more resistance you'll get. That's just how it is with media. You can't make people like it, if they aren't up for it. Maybe try again in a year or two
This, he probably already has some preconceptions about the series. Let him be, he might come around later or never.