I don't feel like I want to look for the original owners of a lost cat
Why don't you want to look for the cat's original owners?
It is such a pain to look for the original owners of the cat, I don't even want it.
A lost cat is something that is not in everyone's best interest, but if someone lost it they would want to know where it is. It is very kind to try to take it in if no one claims it and take care of it. Keep it and see how it reacts with you, and you could end up loving it.
I guess I'll keep the cat for now.
That's so nice of you to give the cat a place to stay. Hold on to it and see if you come across any lost cat ads around the neighborhood. Who knows, maybe there is some kind of reward for anyone that finds it, and you will end up getting paid for a good deed.