|The English letters "orz" are used as an emoticon representing a crouching, defeated person|
That's what the word is meant to be, an encouragement. Try hard, make an effort, do your best. Notice I didn't include any of the other phrases we use to cheer people on in English: you can do it, you got this, go for it, because that kind of confident assurance is missing from 頑張る。
頑張る can be a little dry I think. The effort is all on you, there is no nuance that the person saying it is about to offer help. It became a slogan after the big 2011 Tohoku Earthquake, Ganbarou Japan and Ganbarou Tohoku. I remember reading some (foreign) criticism of the slogan because it was so non-specific. What exactly should we/northeastern Japan work hard at? At penny-pinching so we can give donations of money? At our jobs to boost the economy? At our smiles to change the depressed atmosphere? But the people affected lost their jobs, and in some cases houses and families too. How can they 頑張る？Especially when limited to Ganbaru Tohoku, it sounds like, "Hey we're fine and dandy over here in Tokyo/Osaka/Kyushu but YOU Tohoku, do your best! We'll cheer you on but we don't really want to get involved in the aftermath, haha!"
The non-specific meaning of it can be nice. If you're getting an earful from your boss of all the things you're not doing well, you can just bow and say 頑張ります、頑張ります、without having to name/commit to specific things to improve.
From the boss though, it's the go-to word of encouragement (passive-aggressive criticism?) to young new workers. It's nicer than a dressing-down and it's nicer than saying "you suck" but it still means your current efforts are not enough. Try harder. I think that's why I don't like it. Emotionally, it's a little barb in your soul more often than a healing balm. That sense of 足りない、not enough. You need to try and do more more more.
I often find myself using it only in negative situations. I rarely say it to my husband leaving for work (maybe only when he knows he'll have to turn down another invitation to an after-hours drinking party that day). For example, I show up at work sick. "Leah, are you ok? Can you teach your classes today?" "Yeah I'll be fine. 頑張ります。"
Instead of 頑張って、I want to say, 頑張りすぎないで ganbari-suginaide, "don't try too hard" "don't push yourself" It's what I say to friends starting a new job. 頑張りすぎないで has a sense of knowing your own limits and making boundaries--as workers Americans love that, it's kind of foreign to Japanese though.
However, to the person who ganbarus a lot, there is the lovely reward of one of my absolute favorite words in Japanese: お疲れ様、otsukaresama, "you worked hard today" "thanks for your hard work" It's a typical greeting in Japanese business but sometimes, it means a lot. It's so satisfying. It means you saw and appreciated my efforts. It makes me want to say, "Thank you. Thank you for acknowledging my struggle. I needed that." At the end of a crazy day, the Japanese staff and I all exchange glances, sighs, and little chuckles, and the "Otsukare!" is like the music of angels.
It's true you can't get a rainbow without rain, and you can't really get the full sweetness of otsukaresama without the ganbaru. I just like to say and hear one more than the other--I'm only human!