One Parisian above claims that it takes an hour and a half to cross the city to get from one suburb to another, while it takes 20 minutes by car. That, to me, is a sign that there aren't enough buses filling in the gaps. Here in Martin County, Florida the "bus system" appears to be designed to turn tax money into jobs, rather than provide a useful service, with buses spaced an hour apart, taking an inordinate length of time to cross the county, only offered during daylight hours, and providing no effective county to county service. If they ran every ten minutes, with express buses linking to nearby county systems, I'd probably use it, because I hate driving.
You're thinking of your specific situation. Now think about all the stops those buses serve while they're inconveniencing you. Public transportation runs where the public is. Unless you're a civil engineer with a specialty in public transportation logistics you can't know how they routed and scheduled the buses.
I need to drive to the light rail station that takes me into downtown to my office. I would love to be able to step on a bus that takes me right to the station but there isn't one. Because they're needed to transport people in other places. I could take a bus if I wanted to add 45 minutes to my commute each way.
Yes my commute is longer because I take light rail. I'm lucky I can take light rail. I don't have to deal with traffic, the downtown stop is katty corner from my office building, my company pays for my pass, and parking downtown would be a significant expense. So I'm trading time for money and personally I'm OK with the trade.