I'll respond in two parts:
Statutory compensation (EC261 or similar): I have no hesitation in claiming this where cancellations are due to incompetence, underinvestment etc. and aim to increase the P&L cost of doing it wrong.

Customer service compensation is something I have only sought twice in many hundreds of flights with BA. Once was for a lack of catering - fundamentally, something paid for and not received. The second, and I apologise for the deliberate lack of detail, was for an incident involving some off-duty BA staff who interacted with me in a manner that was out of order. In both cases I was happy to accept a modest quantity of Avios. I have never suffered a non-reclining seat in long-haul F or J, but would be inclined to seek cash or a very substantial Avios sum in that case.

Anything less serious I view as inherent in the business of moving one's self around the planet.