Interaction Design
Five Interaction Design Principles I Return to Every Project
The heuristics that cut through complexity when a design problem feels unsolvable.
February 10, 2025
After years of product design across fintech, SaaS, and B2B platforms, I've distilled my process to a handful of principles I return to whenever a problem feels stuck. These aren't rules — they're lenses.
1. Design for the anxious user first
Most interfaces are designed for the confident, competent user. But anxiety — about losing data, making the wrong choice, being judged — is a near-universal experience in digital products. Especially in fintech.
If your design works for someone who is worried, uncertain, or in a hurry, it works for everyone.
2. Friction is not always the enemy
Removing friction is the default instinct. But friction can be a feature. A confirmation dialog before a destructive action. A required reason field before cancellation. A summary screen before a financial transfer.
Thoughtful friction communicates that an action has weight. It protects users from themselves.
The question is not "how do I remove this friction?" It's "is this friction appropriate to the stakes of the action?"
3. The interface should narrate its own state
Users should never have to wonder what just happened, what's happening now, or what will happen next. If a system is processing, say so. If a form submission failed, say why. If an action is irreversible, say it before, not after.
Silence is the most common interface failure I encounter in production products.
4. Defaults carry enormous weight
The option you pre-select, the amount you pre-fill, the permission you request by default — these are design decisions with outsized behavioral impact. Most users never change defaults.
Design your defaults as if they're the only choice most users will ever make. Because for most users, they are.
5. Complexity is usually a sign of unresolved thinking
When an interface feels complex, it usually reflects unresolved ambiguity upstream — in the product requirements, the business rules, or the team's mental model. Complexity rarely originates in design. It arrives there from elsewhere.
The most valuable design skill is not making complex things look simple. It's pushing the complexity back upstream until the underlying decision gets made.