1. The Kimonos.
2. What on earth are these?
I don't know where these outfits came from, but ABBA never wore them. I believe these costumes first originated when Bjorn Again first started, as can be seen in their video for the song "Stop". Now, almost every single tribute band has these outfits, sometimes with frilly skirts or pleated skirts. Maybe they're based off the Mamma Mia! costumes (which I find to be super outrageous), but ABBA is not the same as Mamma Mia!....
3. Money Money Money
4. Those ridiculous "Swedish" accents.
I can't stand it when tribute bands do those ridiculous "Swedish" accents. They sound... ridiculous. ABBA didn't talk like that. Swedish accents don't sound like that. Just... ditch those stupid accents. Please. ABBA talked in their normal accents, you can too.
There is tons more to talk about with all the things tribute bands get wrong and everything, but my hands are tired from typing, so... :\
Before I end this post, just a little shoutout to ABBA the Show! They wear pants with their kimonos! :D