There's a saying in the comics community, 'you should only make comics using about 60% of your actual skill.' The reason for this is that comics are HARD to make and take a LONG time and if you're giving 100% all the time, you'll burn out fast. I think the same is true for life.
So just like we now know to guard our 'yes', also it's a good idea to guard your 'best'. Save your energy for what matters. I can't help but think of how many employers want their employees to give 110%!!!!! while only paying them minimum wage. It's bullshit lol
I think 'just keep trying your best' sounds like it's a nice thing to say, and I'm definitely overthinking it but, I think we all deserve compassion even if we're not giving it our all. I don't think our first response when comforting someone should be to try and motivate them.