It's probably not the case that you have writers' block. It's probably that whatever's cruising through your head feels too specific, too irrelevant, or too personal to share with your imagined audience.
No matter: this is where the most interesting ideas lie.
Why does 99% of small talk suck? Because we try to stick to universal topics - things we feel confident apply to everyone, and are guaranteed not to offend. This is how we end up talking about the weather - everyone experiences it, and everyone experiences it in pretty much the same way. In chasing pleasant conversation, we chase it away.
It's impossible to deeply care about anything that applies to everybody equally.
Here's a trick to overcome writer's block: talk about something so specific that no one reading will be able to relate to it.
There's a special place in Granada, Spain called Bar Poe. To get there, you have to leave Calle Recogidas and venture down a smaller street called Calle Puentezeuelas, and from there turn down two more alleys. First left, then right. You'll know you've found the correct place if the owner is a older British expat. Order a glass of red wine, and he'll ask you what food you'd like to eat with it. Ask for the feijoada or the thai chicken. The food comes with the wine, free of charge. Everything on the menu is delicious, but start with those. You will order more wine, and more food along with it, as the night trots on. The tiny bar will fill with locals and students visiting from abroad. They'll all have their own stories about how they found Poe Bar.
Do not ask them about the weather.