What is better? (details inside)

Being pleasant. You have and keep more friends that way.

Being smart. Those that matter will not care about you not “being pleasant”.
Those that do take umbrage, are of no value.

Being pleasant is good. But you should be smart enough to know if someone is taking undue advantage of your nature to keep things light and stop them from doing it.

Being pleasant is nice, and it will get you lots of friends.
Being smart will help you avoid making bad decisions, including who you choose as friends.
Being stupid makes you a perpetual victim, including by those you stupidly thought were your friends.
Therefore, I say, being smart is better.
And being smart plus being pleasant is better still.

It’s smart to be as pleasant as possible

Sometimes smart is better and sometimes pleasant and sometimes you can be both together which is best.

I prefer being a pleasant smartass.