Does がち mean "in excess"?


I have been reading a daily article during 朝礼.

One of the sentence used the word がち. The sample sentence is:

> 長所{ちょうしょ}は見逃{みのが}してしまいがちです。
>
> Abundant of misses.

I tried to ask my colleague about the meaning of がち and they said it means [in
excess]. For example if used with しまいがちです it means a lot of misses?

But when I try to look at
[alc.co.jp](http://eow.alc.co.jp/search?q=%E3%81%8C%E3%81%A1%E3%81%A7%E3%81%99&ref=sa)
for examples. There were some with no しまいがち pattern. For example:

> 飛行機や列車の中で『にわか講習会』が始まりがちです。

What does がち mean this time?




In all of your examples, it means "likely to, tend to". It does not mean
"excess".

> 長所は見逃してしまいがちです  
>  'Pros tend to be (unwillingly) overlooked.'
>
> 飛行機や列車の中で『にわか講習会』が始まりがちです  
>  'In airplanes or trains, **" pseudo-workshops" are likely to start**.'
> (Interpretation a)  
>  'In airplanes or trains, "pseudo-workshops" are likely to **start** , (not
> likely to end).' (Interpretation b)  
>  '"Pseudo-workshops" are likely to start **within airplanes or trains** ,
> (not elsewhere).' (Interpretation c)  
>  '"Pseudo-workshops" are likely to start **within** airplanes or trains,
> (not in front them or behind them, etc.).' (Interpretation d)  
>  '"Pseudo-workshops" are likely to start within **airplanes or trains** ,
> (not within busses or cars, etc.).' (Interpretation e)  
>  'In airplanes or trains, **" pseudo-workshops"** are likely to start, (not
> dance parties). (interpretation f)




In all of your examples, it means "likely to, tend to". It does not mean
"excess".

> 長所は見逃してしまいがちです  
>  'Pros tend to be (unwillingly) overlooked.'
>
> 飛行機や列車の中で『にわか講習会』が始まりがちです  
>  'In airplanes or trains, **" pseudo-workshops" are likely to start**.'
> (Interpretation a)  
>  'In airplanes or trains, "pseudo-workshops" are likely to **start** , (not
> likely to end).' (Interpretation b)  
>  '"Pseudo-workshops" are likely to start **within airplanes or trains** ,
> (not elsewhere).' (Interpretation c)  
>  '"Pseudo-workshops" are likely to start **within** airplanes or trains,
> (not in front them or behind them, etc.).' (Interpretation d)  
>  '"Pseudo-workshops" are likely to start within **airplanes or trains** ,
> (not within busses or cars, etc.).' (Interpretation e)  
>  'In airplanes or trains, **" pseudo-workshops"** are likely to start, (not
> dance parties). (interpretation f)

