Don't take 100 miles too literally, I was trying to make a point but if I couldn't fully comprehend the siutation then it may not be a bad idea. We may have to beg to differ a little. X-winds are pretty frequent and if I didn't like those then my flying time would be limited. They are also a known quantity and pretty easy to deal with. TS on the other hand are not. You may see the convection in the distance, but as I have read of what has happened to many others in the past and using my new fangled met knowledge, new CBs can develop around you quite quickly, then it may well be land away and ruin your day or curtains.
Let me start this reply by saying that I think it's unhelpful to second guess other pilots' risk management decisions. That's not just an etiquette thing, it's a realisation that I'm never going to have all the information to allow me to say "you should have stayed" or "you should have gone". So this is an observation about the nature of weather, and not a critique of any decision or decision-making process.
Convective weather (SHRA, TS) and overnight fog/clag are probably the two most common features that get a PROB30/40 or TEMPO on a TAF. In many ways, that's unfortunate, because, while they are both statistical in nature, they are different in a significant way for the pilot.
Fog/clag is statistical because it's very sensitive to small changes in temperature beyond the limits of prediction. But those temperature changes can happen over large areas all at the same time. So when you see every TAF in the SE of England with PROB40 TEMPO 0610 0200 FG, there's a fair chance that most of the SE of England will be socked in and a fair chance that there's won't be fog within 200 miles.
Convection is different. Simple physics suggest that the whole sky cannot be an updraft. So convection has to happen in cells. Those cells
will be somewhere, and, depending on wind speed, they may move. But they won't be
everywhere. That means that it's usually possible to go round convection. You may have to delay your departure for a shower to pass through, you may have to hold for one to pass at your destination, or even divert. But as long as you can see it, and providing you carefully consider your "outs", you can usually make a flight going round the weather. That's not to say that there's "always a way through" -- showers and storms can form in lines.
BTW, I decided not to fly today (Sat) too. Not uniquely dangerous but: EGLF 030910Z 031019 25015KT 9999 SCT025 TEMPO 1019 25018G28KT 8000 SHRA PROB30 TEMPO 1019 4000 +SHRA BKN025CB
Cloud base is marginal, G28 is going to happen at some point. PROB30 is unlikely, but if it does then am certain I will be in trouble.
You won't be in trouble if you don't fly into it. Even heavy convection tends to be no more than 10 miles across. So have a plan, and be prepared to turn round.