I got tough-love comments only about twice in my postgraduate academic training prior to becoming a PI.
Once was from a friend in a far different graduate program when I was in the depths of writing my dissertation. This one is in my top 5 life touch-stone conversations I would guess. Basically it boiled down to "If you find all of this so unpleasant, get the hell off your ass and do something else. I mean seriously, wtf is wrong with you?"
The second tough-love convo came from a mentor who had just seriously pulled the rug out from under me and I had disappeared (essentially) from work for several weeks. That one was more----nuanced in effect on me. But in the end s/he was right. Shitty things happen but dude, it's your fricken career and your fricken life. So sack up and get back to work.
On reflection, I didn't have anywhere near enough people doing this to me throughout my career. Two was not by any means as many as I could have benefitted from.
As a mentor, I rarely start these conversations. I doubt I've had a trainee that doesn't get at least one such conversation from me that could qualify, but I find them unpleasant and avoid them.
No doubt just as my mentors did.
They are hard conversations to initiate and hard ones to receive.
Even on the Internet from some anonymous blowhard.