Mixed perfect & imperfect sentences

Question

Choice of perfect vs imperfect in this sentence "Il a commencé à sourire aux gens qu'il croisait dans la rue" appears completely random - why not the other way round - or both the same tense?  He meets people regularly but he only smiles irregularly?  What an infuriating language!

Accepted Answer

Hi Philip,
Not sure that I understand your frustration.
"Il a commencé (commencer in the perfect) à sourire aux gens qu'il croisait (croiser in the imperfect) dans la rue" 
The guy has started to smile at people he was passing in the street but he wasn't doing this before. So the first conjugation is correct -- completed action. and the second is also correct habitual past action (every time he passes people in the street)
Sorry if I'm missing your point, but this is how I see it.
Jim