No idea what country are you from but it might be that the avocados you get there are just not that good. I’m from Chile (South America) and here some eat avocados almost daily, my family sure does.

To be clear, the avocado should be soft when you squeeze it, but not too much as to be easily smashed, like an orange but maybe softer. If it’s firm like an apple, it’s not ripe yet. If it’s too soft, it may have gone wrong already and will have an acid taste and rancid smell.

Image for reference.

Another thing to look for is the little hole / part where the branch connects to the avocado (left part on the image). It sometimes falls off, so if it looks white, the avocado may have started to rot from there inwards; that whole should ideally look brownish, green it’s good too.

Just cut it in half, take the seed off (just use this tip, hit the seed with a sharped knife and twist it, otherwise you may have an avocado hand incident). Take it off the skin with a spoon and smash it with a fork, then imply add salt.