The simple past

I don't know if I'm just a stickler about this, but I constantly change "was spending" to "spent", "were going" to "went", and so on.  I have a theory that because in B/C/S you say "isao sam" that it just seems natural for people to write a compound form for the past.  This is another one of my top 10 things I'd drill into every English learner.