I think the worst thing Valve ever did to TF2 was introduce Unusuals. Never liked them, never had any interest in getting one. Gaudy, random particle effects that make no sense. It was easier to tolerate in the early years as they were so rare but nowadays there's at least one person in any given server looking like an idiot with one.

If they were designing the TF2 monetization these days I'd like to think they'd go a different route for the high ticket item, but people who actually buy into this shit really fall for conspicuous consumption.