It’s natural to want to do your best. We all want to do our best all the time… but the nature of “the best” is just that, the best you’ve ever done. Meaning you probably aren’t going to be putting in a performance on any given day that’s as good as “the best” you’ve ever done. If you’re constantly comparing your current lifting numbers to your PRs, you’re going to be disappointed. What’s more prudent is to compare yourself to your average. It sets you up for a more realistic comparison, and gives you a baseline you can realistically stand to beat on any given day. This is good motivation, and also yields good long-term results because Trajectory Matters More Than Results in the short term.
Don't
Alright my best Squat was 315x3, today I’m doing 225. I’m sad.
Do
Alright my past 5 Squats have been at about 215, today I’m improving that.