What do you usually prefer: singles, express bets or systems? ?

What do you usually prefer: singles, accumulators, or systems? I often gravitate toward accumulators because of the high odds, but they're often the ones that fail. Maybe it's the other way around for others? I'd love to hear real-world experience - what leads to winnings more often, and what to long-term losses? Maybe I'm just choosing events incorrectly.