I don’t think the problem is that I think it is hard. It’s more like that I end up thinking something else, like in daydreaming or unintentionally in meditation. Which is why meditation helps with it.
The second alternative is that I’m too conflicted about the thing I’m trying. But that would call for conflict-resolution technique rather than motivation technique. :)
I think there’s also the question if the “I’d rather just be friends.” said in the context of rejecting an invite to a date actually means “I want to be your friend.” or is just a polite way of saying “I don’t want to go on a date with you.”. In the former case trying to cultivate a friendship will be more useful than in the latter...